JUNIOR CERTIFICATE EXAMINATION 2012 MARKING SCHEME MATHEMATICS ORDINARY LEVEL PAPER 1 Page 1 GENERAL GUIDELINES FOR EXAMINERS 1. Penalties of three types are applied to candidates’ work as follows: Blunders - mathematical errors/omissions (-3) Slips- numerical errors (-1) Misreadings (provided task is not oversimplified) (-1). Frequently occurring errors to which these penalties must be applied are listed in the scheme. They are labelled: B1, B2, B3,…, S1, S2,…, M1, M2,…etc. These lists are not exhaustive. 2. When awarding attempt marks, e.g. Att(3), note that any correct, relevant step in a part of a question merits at least the attempt mark for that part if deductions result in a mark which is lower than the attempt mark, then the attempt mark must be awarded a mark between zero and the attempt mark is never awarded. 3. Worthless work is awarded zero marks. Some examples of such work are listed in the scheme and they are labelled as W1, W2,…etc. 4. The phrase “hit or miss” means that partial marks are not awarded – the candidate receives all of the relevant marks or none. 5. The phrase “and stops” means that no more work is shown by the candidate. 6. Special notes relating to the marking of a particular part of a question are indicated by an asterisk. These notes immediately follow the box containing the relevant solution. 7. The sample solutions for each question are not intended to be exhaustive lists – there may be other correct solutions. 8. Unless otherwise indicated in the scheme, accept the best of two or more attempts – even when attempts have been cancelled. The same error in the same section of a question is penalised once only. 9. 10. Particular cases, verifications and answers derived from diagrams (unless requested) qualify for attempt marks at most. 11. A serious blunder, omission or misreading results in the attempt mark at most. 12. Do not penalise the use of a comma for a decimal point, e.g. €5.50 may be written as €5,50. Page 2 BONUS MARKS FOR ANSWERING THROUGH IRISH Bonus marks are applied separately to each paper as follows: If the mark achieved is 225 or less, the bonus is 5% of the mark obtained, rounded down. e.g. 198 marks 5% 9.9 bonus 9 marks. If the mark awarded is above 225, the following table applies: Bunmharc Marc Bónais Bunmharc Marc Bónais (Marks obtained) (Bonus Mark) (Marks obtained) (Bonus Mark) 226 11 261 – 266 5 227 – 233 10 267 – 273 4 234 – 240 9 274 – 280 3 241 – 246 8 281 – 286 2 247 – 253 7 287 – 293 1 254 – 260 6 294 – 300 0 Page 3 QUESTION 1 Part (a) Part (b) Part (c) 10 marks 20 (5, 5, 5, 5) marks 20 (10,5,5) marks (a) 1. Att (3) Att (2, 2, 2, 2) Att (3,2,2) 10 marks (a) S = , , , , Att 3 P = , , Fill the elements of S and P into the following diagram. S P (a) 10 marks S Att 3 P r p s w u t Slips ‐1 S1 Each element incorrectly filled into diagram S2 Each element omitted from diagram but see W1 S3 Each unlisted element used but see W1 (some relevant element must be present to use S3) Misreading (-1) M1 Interchanging S and P totally Attempts (3 marks) A1 Totally incorrect filling of the Venn diagram using given elements A2 Correct number of dots in each set without labels Worthless (0) W1 No filling in of the Venn diagram or use of unlisted elements only but see S3 Page 4 (b) 20 marks (5,5,5,5) Att 2,2,2,2 (b) A = {1, 2, 3, 6} is the set of the divisors of 6. B A B = {1, 2, 4, 8} is the set of the divisors of 8. .3 .1 .2 .6 C = {1, 2, 4, 5, 10, 20} is the set of the divisors of 20. .5 .10 .20 .8 .4 C List the elements of: (i) B∪C (ii) A \ B C (iii) BC (iv) the common divisors of 6, 8 and 20. (i) 5 marks Att 2 B∪C= {1,2,4,5,8,10,20} Blunders (-3) B1 Any incorrect set of the elements of B and C other than the misreading below Misreading (-1) M1 B∩C = {1, 2, 4} Attempts (2 marks) A1 3or 6 appear in the answer (ii) 5 marks A \ B C {3,6} Blunders (-3) B1 Any incorrect set of the elements of A, B and C Misreading (-1) M1 (A\B) ∪C = {3,5, 6,10 ,20,1,2,4 } Page 5 Att 2 (iii) 5 marks B C= Att 2 {1, 2, 4} Blunders (-3) B1 Any incorrect set of the elements of A, B and C other than the misreading below Misreading (-1) M1 B C giving {1, 2, 4, 5, 8, 10, 20} Attempts (2 marks) A1 1, 2 or 4 appear in the answer (iv) the common divisors of 6, 8 and 20 5 marks = { 1, 2 } Att 2 Slips (-1) S1 Each missing or incorrect element to a max of 3 Attempts ( 2 marks) A1 Any correct divisors of 6,8 or 20 appears, but see S1 A2 Ans. 120 Worthless (0) W1 Elements listed that are not divisors of 6, 8 or 20 (c) 20 ( 10,5,5) Marks Att 3,2,2 (c) In a survey, 60 households were asked if they had a cat (C) or a dog (D). 20 said they had a cat. 25 said they had a dog. 12 said they had both a cat and a dog. (i) Represent this information in the Venn diagram below. C (ii) D How many households had only a cat or a dog? (iii) What percentage of households had neither a cat nor a dog? Page 6 (c)(i) 10 marks Att 3 C D 8 12 13 27 Blunders (-3) B1 Each incorrect or omitted entry (unless consistent error) in Venn diagram subject to S1 below. Slips (-1) S1 Numerical errors where work is clearly shown Misreading (-1) M1 Interchanges cats and dogs Attempts (3 marks) A1 Any one correct/relevant entry c(ii) 5 marks Att 2 8 + 13 = 21 *A correct answer written in the space provided takes precedence over an incorrect Venn diagram. *Accept candidates work from previous part c (i). Blunders (-3) B1 Any incorrect use of the given numbers or the numbers from the candidates incorrect Venn diagram [Subject to S1]. Slips (-1) S1 Numerical errors where work is clearly shown S2 Fails to add their correct relevant 2 figures Page 7 c(iii) 5 marks Att 2 27 100 45% 60 *A correct answer written in the space provided takes precedence over an incorrect Venn diagram. *Accept candidates work from previous parts (c) (i), (c) (ii). Blunders (-3) B1 No work shown B2 Mishandles the percentage B3 Any incorrect use of the given numbers or numbers from the previous work [Subject to Second *above] B4 Fails to find the percentage Misreading (-1) M1 × 100 or similar and continues Slips (-1) S1 Numerical errors where work is clearly shown, to a max of 3 Attempts (2 marks) A1 Any one correct/relevant step A2 100 appears Worthless (0) W1 Incorrect answer with no work shown Page 8 QUESTION 2 Part (a) Part (b) Part (c) 10 marks 20 (10,5, 5) marks 20 (5, 10, 5) marks (a) 10 marks (a) 10 marks 1costs Att 3 3 packets of soup cost €3‧51. What would be the cost of 5 packets of the same soup? (a) Att 3 Att (3 ,2, 2) Att (2, 3,2) . = 1.17 Or 3:5 Att 3 Or . 5 cost 1.17 × 5 =5.85 Ans 5.85 = 1.17 1.17 × 5 = 5.85 3:5 = 3.51 : x *Correct answer without work 7marks *Special Case 3.51 2.106 7 marks . *Stops at 1.17 or *Stops at 3.51 × 5 (=17.55) 4marks (no use of 5, B(-3) and B4 or B5) 4 marks ( no use of 3 and possible slips) Blunders (-3) B1 Divisor ≠ 3but see above B2 incorrect multiplier B3 5:3 = 3.5 : x and continues B4 Error in decimal point (apply once) B5 Fails to finish Slips (-1) S1 Numerical errors where work is clearly shown, to a max of -3 Attempts (3 marks) A1 Indicates or 3:5 or 3.51: x only and stops or ( only) appear with no work shown A2 1.17 or 17.55 or A3 A4 A5 only appears (3.51×3) or (3.51÷5) and stops 3.51 is multiplied or divided by any wrong number correctly Worthless (0) W1 Incorrect answer without work but see A1 and A2 W2 3.51 + 3 = 6.54 or similar, and stops Page 9 . = 3x = 3.51 × 5 = 17.55 . x= = 5.85 (b) 20 marks (10, 5, 5 ) (b) (i) Att (3, 2, 2) By rounding each of these numbers to the nearest whole number, 24 231 estimate the value of . 15 6 3 78 . 24 231 is approximately equal to: 15 6 3 78 = = – (ii) Using a calculator, or otherwise, find the exact value of 24 231 . 15 6 3 78 (iii) Find the difference between the exact value in (ii) and the estimated value in (i). b(i) 10 marks Att 3 24 231 is approximately equal to: 15 6 3 78 24 24 = 16 – 4 = 2 12 24 24 24 * 16 4 and stops or 16 4 = 12 7 marks *No penalty if the intermediate step between approximations and final answer not shown i.e. 24 not shown. 10 marks. 12 *Special Case: 24 231 = 2.05 15 6 3 78 in this part → 3 marks. Page 10 Blunders (-3) B1 B2 B3 B4 B5 Correct answer without work Error(s) in rounding off to the nearest whole number (once only if consistent) Decimal error in calculation of approximate value An arithmetical operation other than indicated. – 4 = –2.5 or (24÷4 –16) = –10 (breaking order) or similar and continues Slips (-1) S1 Numerical errors to a max of -3. Attempts (3 marks) A1 Only one or two approximations made to the given numbers and stops Worthless (0) W1 Wrong answer without work but note Special Case above b(ii) 5 marks Att 2 24 231 24 231 2 05 15 6 3 78 11 82 Blunders (-3) B1 Decimal error or early rounding off B2 Fails to finish B3 Treats as (24.231÷15.6) –3.78 = -2.226730769… B4 Treats as: (24.231÷3.78) –15.6 = -9.18968254… B5 Treats as: 24.231÷(15.6 + 3.78) = 1.250309598… B6 Treats as:. 24.231÷(15.6×3.78) = 0.410917785… Slips (-1) S1 Numerical errors to a max of 3 Attempts (2 marks) A1 Any correct relevant step and stops. A2 Any of the following (see above): -2.226730765…, 9.18968254…, 1.250309598…, 24.231 24.231 0.410917785… or = 1.553269231 or = 6.41031746 (minimum 4 decimal 15.6 3.78 places) with or without work Worthless (0) W1 Wrong answer without work but see A2 Page 11 b(iii)` 2·05 – 2·00 = 0·05 5 marks or -2= Att 2 *Allow candidate’s figures Blunders (-3) B1 Fails to finish B2 Decimal error (once only if consistent) B3 Finds the sum of (i) and (ii) Slips (-1) S1 Numerical errors to a max of -3 Attempts (2 marks) A1 Any relevant step i.e. transfers answers from (i) and/or (ii) Worthless (0) W1 Incorrect answer without work (c)` (c) 20 (5,5,5,5) marks (i) Att 2,2,2,2 Using a calculator, or otherwise, multiply 450 000 × 7‧8. Then express your answer in the form a ×10n, where 1≤ a <10 and n ℕ. (ii) (iii) a7 in the form a n , where n ℕ. a3 117 Hence or otherwise evaluate . 113 Write It takes three workers four days to build a wall. How long would it take two workers to build the same wall? c(i) 5 marks 450 000 × 7·8 = 3 510 000 = 3·51 ×106 * 3.51 or 3.51 × 106 (without work) → 4 marks Blunders (-3) B1 Decimal error B2 An arithmetic operation other than that indicated e.g. 450000÷7.8 = 57692.30789 Slips (-1) S1 Numerical errors to a max of -3 S2 Rounds off to 3 ×106 S3 Incorrect format, where a 1 or a 10 and n Z S4 Finds 3 510 000 and stops Attempts (2 marks) A1 Any relevant step and stops Page 12 Att 2 c (ii) 5marks a7 a3 a73 a 4 or Att 2 a a a a a a a a7 3 = a4 aaa a * a a a a and stops 4marks * a7-3 and stops 4marks Blunders (-3) B1 Each error in calculation involving indices B2 Each incorrect number of a’s in the extended form B3 Each incorrect elimination of the a’s in extended form Slips (-1) S1 Numerical errors to a max of -3 Attempts (2 marks) A1 Some correct manipulation of indices A2 4 only written down Worthless (0) W1 Writes a only or incorrect answer with no work shown other than A2 c(ii)Hence 5 marks 7 11 3 114 14641 11 *Accept candidate’s answer from above unless it oversimplifies the question Blunders (-3) B1 Each error in calculation involving indices B2 Each incorrect number of 11’s in the extended form B3 Fails to finish B4 Each incorrect elimination of the 11’s in extended form Slips (-1) S1 Numerical errors to a max of -3 Attempts (2 marks) A1 Some correct manipulation of indices A2 112= 121 or similar and stops A3 Candidate transfers their answers from above Worthless (0) W1 Incorrect answer with no work shown Page 13 Att 2 c(iii) 5 marks 1 man takes 3×4 days = 12days 12 2 men take 6 days 2 * Special case: 4 2 8 →2 marks 3 3 4 ( 2) * Stops at 2 →2 marks Blunders (-3) B1 Incorrect answer without work B1 Divisor ≠ 2 and continues B2 Incorrect multiplier (≠3) or fails to multiply, or fails to multiply but see 1st * Slips (-1) S1 Numerical errors where work is clearly shown to a max of -3 Attempts (2 marks) A1 Mentions one man or man days A2 12 or 2 only appear (no work shown) 4 A3 4×2 or 3 and stops A4 4 is multiplied or divided by any wrong number, correctly Worthless(0) W1 Incorrect answer without work but see A2 above W2 3 + 4 = 7 or similar W3 hours only with no mention of 3 or 4 or (96 on its own) Page 14 Att 2 QUESTION 3 Part (a) Part (b) Part (c) 10 marks 20 (10,10) marks 20 ( 10, 10) marks (a) 3. 10 marks (a) Att 3 The cost of a holiday came to €2400. This was made up of the cost of travel, accommodation and spending money. 3 of the cost was for travel and accommodation. 5 How much spending money was there? (a) 10 marks 3 × 2400 = 1440 5 2400 –1440 = €960 * Att 3 Att (3 ,3) Att (3,3) 3 2 travel + acc => spend. 5 5 2 ×2400 = €960 5 Att 3 3 2 =60% => = 40% 5 5 40 2400× = €960 100 No penalty for omitting € symbol Blunders (-3) B1 Correct answer without work 3 B2 2400 ÷ (method 1) 5 2 B3 2400 ÷ (method 2) 5 B4 Calculates the travel and accommodation and stops (method 1 ) B5 Operation other than subtraction in final step or omits final step. (method 1) B6 Finds 60% 0f 2400 and stops (same as B5) Slips (-1) S1 Numerical errors (to max -3) Attempts (3 marks) A1 Any attempt at getting A2 Writes down 3 2 of 2400 or of 2400 5 5 2 or 40% 5 Page 15 (b) 20 (10,10) Marks (b) (i) Amanda borrows €1000. She agrees to pay it back at €90 per month for a year. How much interest will she pay? (ii) Att (3,3) A computer is ordered online. It is advertised for €550 plus VAT at 23%. There’s a delivery charge of €7‧50. What is the total cost to be paid? (b) (i) 10 marks Att 3 Amanda borrows €1000. She agrees to pay it back at €90 per month for a year. How much interest will she pay? b(i) 10 marks 90×12 = 1080 Int: 1080 – 1000 = €80 * No penalty for omitting € symbol Blunders (-3) B1 Correct answer without work B2 90× 12=1080 and stops B3 90÷ 12 = 7.5 and continues correctly B4 Multiplies 90 by some whole number other than 12 and continues B5 Fails to finish Slips (-1) S1 Numerical errors (to max -3) Attempts (3 marks) A1 Oversimplification A2 Multiplies 90 by some number other than 12 and stops Page 16 Att 3 (b) (ii) 23 % = VAT = 550 = 126.50 Total Cost = 550 + 126.50 + 7.50 = €684 10 marks 100% = €550 1% = 123% = att 3 550 123 1.23 €676.50 Total Cost = €676.50 + 7.50 = €684 = 5.50 123 = 676.50 Total Cost = €676.50 + 7 .50 = €684 * No penalty for omitting € symbol Blunders (-3) B1 Correct answer without work B2 Decimal error and continues (giving answers 2391.30 or 447.51) B3 Inverts as B4 Mishandles 23 % eg 550 23 550 23 Note: (550 must be used} B5 550 taken as 123% and finds his 100% and continues B6 No addition of VAT (as per candidates work) to the bill B7 No addition of the delivery charge B8 Subtraction of VAT ( as per candidates work) from the bill B9 No addition of 550 Slips (-1) S1 Numerical errors to a max of -3 Misreadings (-1) M1 Reads as 32% or €500 Attempts (3 marks) and stops or and stops A1 A2 100% = 550 and stops A3 100 and stops or and stops A4 550 23 % and stops A5 €550 + 7.50 and stops Worthless (0) W1 Incorrect answer without work W2 550 + 23 = €573 and stops or continues Page 17 Part (c) 20(10,10) marks (i) A work of art is priced at €6600. After VAT is added it costs €7491. Calculate the amount of VAT and the rate of VAT. (ii) Att (3,3) Ronan was given a bicycle which was in need of repair. For the repairs, he spent €60 on spare parts and €12 on paint. When it was repaired he sold it for €95. Calculate the profit he made as a percentage of his costs. Give the percentage to the nearest whole number. (c) (i) 10 marks A work of art is priced at €6600. After VAT is added it costs €7491. Calculate the amount of VAT and the rate of VAT. Att3 (c) (i) Att3 10 marks 7491 – 6600 = 891 = VAT 100 13.5% * No penalty for omitting € symbol *7991 – 6600 = 891 = 13.5% → 10 marks *Stops after €891 → 4 marks ( and stops still only 4 marks) Blunders (-3) B1 Correct answer without work. B2 Decimal error eg 1.35% B3 Inverts as and continues ( to get 740.74 %) B4 7461 + , by 6600 and continues correctly B5 Mishandles the finding of the rate of vat 100 to get 11.89% = 12% B6 B7 Rounds off to 14% without showing 13.5% B8 Fails to finish Slips (-1) S1 Numerical errors (apart from decimal errors) max of -3 Attempts (3marks) A1 Some use of 100 A2 Some attempt at subtraction Page 18 (c) (ii) 10 marks Att3 Ronan was given a bicycle which was in need of repair. For the repairs, he spent €60 on spare parts and €12 on paint. When it was repaired he sold it for €95. Calculate the profit he made as a percentage of his costs. Give the percentage to the nearest whole number. (c) (ii) 60 + 12 = 72 95 – 72 = €23 Profit 100 31.944 = 32 % 10 marks Att3 60 + 12 = 72 100 131.944% (132% accept) 131.944 – 100 = 31.944 = 32% * No penalty for omitting € symbol *Answer €23 → 4 marks * 100 and stops → 6 marks Blunders (-3) B1 Correct answer without work B2 Adds €95 to €72 and continues B3 Calculates profit as percentage of selling price. ie. B4 Divisor not equal to 72 B5 Mishandles the calculation of profit as a percentage B6 Fails to multiply by 100 Slips (-1) S1 Numerical errors to a max of -3 S2 Fails to round off to the nearest whole number Attempts (3 marks) A1 Some indication of subtraction A2 Some use of 100 A3 60 +12 (= 72) Worthless (0 marks) W1 Incorrect answer without work = 0 marks. Page 19 100 24.21% 24% QUESTION 4 Part (a) Part (b) Part (c) (a) (a) 15(10,5) marks 15 (5,5,5) marks 20 ( 5,5, 10) marks 10,5 marks If a = 4 and b = 5, find the value of: (i) 2a + b (ii) ab – 3 (a)(i) 10 marks Att 3,2 Att (2,2 ,2) Att (2,2,3) Att 3,2 Att 3 (i) 2a + b = 2(4) + 5 = 8 + 5 = 13 *8 +5 (only) → 9 marks *One substitution coupled with an implied substitution leading to correct answer e.g. = 2a +5 = 13 10 marks. Blunders (-3) B1 Correct answer without work B2 Leaves 2(4) in the answer B3 Breaks order i.e. 2(4+5) = 18 B4 Treats 2(4) as 6 or 24 Slips (-1) S1 Numerical errors to a max of 3 S2 Values of a and b interchanged. Misreadings (-1) M1 Incorrect numerical substitution for either a or b, but not both, and continues (See W1) or a + 2b calculated out Attempts (3 marks) A1 Incomplete substitution and stops e g 2a + 5 Worthless (0) W1 Incorrect substitution for both a and b Page 20 (a)(ii) (ii) ab – 3 = 4×5 – 3 = 20 – 3 = 17 5 marks Att 2 *20 – 3 (only) → 4 marks *One substitution coupled with an implied substitution leading to correct answer e g 4b –3 = 17 or 5a – 3 =17 5 marks Blunders (-3) B1 B2 B3 B4 Correct answer without work Leaves 4(5) in the answer Breaks order i.e. 4(5-3) = 8 Treats 4(5) as 9 or 45 Slips (-1) S1 Numerical errors to a max of -3 Misreadings (-1) M1 Incorrect numerical substitution for either a or b, but not both, and continues (See W1) Attempts (2 marks) A1 Incomplete substitution and stops e g 4b -3 Worthless (0) W1 Incorrect substitution for both a and b. Page 21 (b) (b) 15 (5,5,5) Marks Att 2,2,2 f(x) = 2x – 1. (i) Draw a graph of f(x) in the domain –1 ≤ x ≤ 1, xℝ. (ii) Use your graph to estimate the value of x when f(x) = 0. (b)(i) f(x) = 2x – 1 f(-1) = 2(-1) – 1= -2 -1 = -3 (-1,-3) f(0) = 2(0 )– 1 = 0 – 1 = -1 (0,-1) f(1) = 2(1) – 1= 2 – 1 = 1 (1,1) 5 marks OR OR f(x) = 2x – 1 f(-1) = 2(-1) – 1 = -3 (-1,-3) f(0) = 2(0 )– 1 = -1 (0,-1) f(1) = 2(1) – 1 = 1 (1,1) Att 2 x -1 0 1 2x -1 -2 -1 0 -1 +2 -1 f (x) -3 -1 1 * Error(s) in each row/column calculation attracts a maximum deduction of 3marks * 2 points correct (full marks) _ (need not be in domain) Blunders (-3) B1 “+2 x ” taken as “2” all the way. [In the row headed “+2 x ” by candidate] B2 “-1” calculated as “- x ” all the way. [In the row headed “-1” by candidate] B3 Adds in top row when evaluating f (x) in Box B4 Omits “-1” row B5 Omits “+2 x ” row B6 Takes 2x as 2 + x and applies it in his calculations B7 Each incorrect image without work i.e. calculation through the function method Slips (-1) S1 Numerical errors to a max of -3 in any row / column Misreadings (-1) M1 Misreads -1 as +1 and places +1 in the table or function. M2 Misreads “ 2 x ” as “ 2 x ” and places “ 2 x ” in the table or function Attempts (2 marks) A1 Any effort at calculating point(s) A2 Only one point calculated and stops Page 22 (b)(ii) 5 marks Att 2 2 1 -1 1 -1 -2 -3 -4 * Answers need not be written in table. . *Accept candidate’s value from (i) but see B1 and S4 (see S2) *Tolerance ± 0.5 ( ± 1Box on grid) *Correct graph but no table award full marks i.e. (5 + 5) *Only one correct point graphed correctly but no table Att 2 + Att 2 *Accept reversed co-ordinates if (i) if axes not labelled or (ii) if axes are reversed to compensate (see B1 below) Blunders (-3) B1 Full domain not covered B2 Scale error (once) B3 Reversed co-ordinates plotted against non-reversed axes (once only) {See 6th * above} Slips (-1) S1 All points not joined or joined in incorrect order S2 Each incorrectly plotted point S3 Each point { 2 points needed } from table not graphed [ See 2nd * above ] S4 Not a straight line if not already penalised in b(i) or b(ii) but see 2nd * Attempts (2 marks) A1 Graduated axes (need not be labelled) A2 Some effort to plot a point { See 2nd * above} A3 Random straight line with or without axes A4 One correct point, with /without work Page 23 b(iii) Answer to be written here: 5 marks x= 0·5 Att 2 when f(x) = 0 * Allow candidate’s figures Blunders (-3) B1 Fails to finish but draws some relevant line Slips (-1) S1 Numerical errors to a max of -3 S2 Correct answer indicated and/or written on graph only Attempts (2 marks) A1 Some correct indication on graph A2 Attempts at algebraic evaluation or calculator A3 Finds answer -1 i.e. find x = 0 (where crosses y-axis) Worthless (0) W1 Wrong answer without work (c) (c) (i) (ii) 20(5,5,10) marks Conor spent € y on a book. He then spent € (4y + 6) on a football jersey. In total, he spent €61. Write an equation in y to represent this information. Solve your equation from (i) to find the value of y. (iii) Solve the equation: c(i) x2 – 5x – 14 = 0. 5 marks Att 2,2,3 Att 2 y + 4y + 6 = 61 5y + 6 =61 Blunders (-3) B1 Incorrect expression for the cost of a book and football jersey other than misreading below Slips (-1) S1 No 61 included in answer Misreadings (-1) M1 Answer given as y + 4y – 6 = 61 or similar Attempts (2 marks) A1 Any effort at forming an expression (y included) Worthless (0) W1 Cost of book given as a constant Page 24 c(ii) * 5 marks Att 2 5y + 6 =61 5y + 6 – 6 = 61 – 6 5y = 55 y = 11 Accept candidates answer from previous work. Blunders(-3) B1 Correct answer without work B2 Error in forming equation B3 Distribution error B4 Transposition error B5 Stops at 5y = 55 or fails to solve equation B6 Error in collecting like term Misreadings (-1) M1 Transfers information in (i) incorrectly if not oversimplied Slips (-1) S1 Numerical errors to a max of -3 Attempts (2 marks) A1 Answer from part c (i) written down and stops. A2 Any effort at forming an expression A3 Any effort at solving their equation A4 Successful Trial and Error Worthless (0 marks ) W1 Incorrect answer with no work c(iii) x2 - 5x – 14 = 0 x2 - 7x + 2x – 14 = 0 x(x -7) + 2(x – 7) = 0 (x + 2)(x – 7) = 0 (x + 2) = 0 or (x – 7) = 0 x = -2 or 10 marks x - 5x – 14 = 0 Att 3 2 5 x +2 x 7 x=7 (x + 2) = 0 or (x – 7) = 0 x = -2 * * or 52 41 14 21 5 25 56 5 9 2 2 4 14 2 and 7 2 2 x=7 2 correct solutions by Trial and Error 1 correct solution by Trial and Error Page 25 10 MARKS 3 MARKS (Attempt) Blunders (-3) Factor Method B1 Correct answers without work B2 Incorrect two term linear factors of x2-5x -14 formed from correct (but inapplicable) factors of x 2 and/or ±14,e.g. (x+14)(x-1) B3 No roots given, or two incorrect roots (once only) B4 Incorrect factors of x 2 and/or ±14 B5 Correct cross method but factors not shown and stops [Note: B3 applies also] B6 x(x–7) + 2(x–7) or similar and stops [Note: B3 applies also]. B7 Error(s) in transposition Slips (-1) S1 Numerical errors to a max of -3 S2 One root only from factors Attempts (3 marks) A1 Some effort at factorization e.g. (x A2 States one correct root without work )( ) or the cross with at least one “x” written in Worthless (0 marks) W1 x2 –5x = 14 or similar and stops W2 Incorrect Trial and error W3 Oversimplification, resulting in a linear equation Formula Method Blunders (-3) B1 Error in a,b,c substitution (apply once only) B2 Sign error in substituted formula (apply once only) B3 Error in square root or square root ignored B4 Stops at B5 Incorrect quadratic formula and continues Slips (-1) S1 Numerical errors to a max of -3 p S2 Roots left in the form q S3 One root only Attempts (3 marks) A1 Correct formula and stops A2 One correct substitution and stops Page 26 QUESTION 5 Part (a) Part (b) Part (c) 10 marks 20 (5,5.10) marks 20 ( 10, 10) marks (a) (a) 10 marks Simplify fully 2(x + 1) + 5(2x + 3). (a) 2(x + 1) + 5(2x + 3) = 2x +2 +10x +15 = 12x + 17 Att 3 Att (2,2,3) Att (3,3) Att 3 10 marks Att 3 * * Stops after correct removal of brackets Gathering of terms at most one blunder 7 Marks Blunders (-3) B1 Correct answer without work B2 Error(s) in distribution (each time) B3 Combining unlike terms after removal of brackets and continues B4 Fails to group like terms B5 Fails to finish Slips (-1) S1 Numerical errors to a max of -3 Misreadings (-1) M1 2(x+2) and continues Attempts (3 marks) A1 Any one term correctly multiplied A2 Combines unlike terms at the start and finishes correctly Worthless (0) W1 Combining unlike terms before attempting multiplication and stops e.g. 5(5x) = 25x Page 27 (b) 20 (5,5,10) marks (i) (ii) (iii) Att 2,2,3 Factorise 5xy + 3y. Factorise ax + 2ay + 3x + 6y. Solve for x and y: 2x + 5y = 19 3x – y = 3 b((i) 5 marks Att 2 5xy + 3y = y(5x + 3 ) Blunders (-3) B1 Removes factor incorrectly Attempts (2 marks) A1 Indication of common factor e g underlines y’s and stops b(ii) 5 marks ax + 2ay + 3x + 6y = a(x + 2y) + 3(x + 2y) or x(a+3) + 2y(a + 3) = (a + 3)(x + 2y) = (a+3)(x+ 2y) *Accept also (with or without brackets) for 5 marks any of the following (a+3) and (x+2y) [The word and is written down.] (a+3) or (x+2y) [The word or is written down.] (a+3), (x+2y) [A comma is used] Blunders (-3) B1 Correct answer without work B2 Stops after first line of correct factorization e.g. a(x + 2y) + 3(x + 2y) or equivalent i,e. x(a + 3) + 2y(a + 3) B3 Error(s) in factorising any pair of terms B4 Correct first line of factorisation but ends as (a+3).2xy or equivalent Slips (-1) S1 (a+3) (x+2y) Attempts (2 marks) A1 Pairing off, or indication of common factors and stops A2 Correctly factorises any pair and stops Page 28 Att2 b (iii) 10 marks 2x + 5y = 19 3x – y = 3 X5 OR 2x + 5y = 19 15x – 5y = 15 17x = 34 x= 2 2(2) + 5y = 19 4 + 5y = 19 6x +15y = 57 -6x+2y = -6 Or 17y = 51 y=3 Att 3 3x -3 = y 2x +5(3x-3) = 19 2x +15x – 15 = 19 17x = 19 + 15 2x + 15 = 19 17x = 34 2x = 4 x=2 x=2 4 + 5y = 19 5y = 15 y =3 y=3 *Apply only one blunder deduction (B2 or B3) to any error(s) in establishing the first equation; in terms of x only or the first equation in terms of y only *Finding the second variable is subject to a maximum deduction of -3 Blunders (-3) B1 Correct answers without work (stated or substituted) B2 Error or errors in establishing the first equation in terms of x only (17x = 34) or the first equation in terms of y only (17y = 51) through elimination by cancellation (but see S1) B3 Error or errors in establishing the first equation in terms of x only (17x = 34) or the first equation in terms of y only (17y = 51) through elimination by substitution (but see S1) B4 Errors in transposition when finding the first variable B5 Errors in transposition when finding the second variable B6 Incorrect substitution when finding second variable B7 Finds one variable only Slips (-1) S1 Numerical errors to a max of -3 Attempt (3 marks) A1 Attempt at transposition and stops A2 Multiplies either equation by some number and stops A3 Incorrect value of x or y substituted correctly to find his correct 2nd variable A4 One correct answer without work (stated and substituted) Worthless (0 marks) W1 Incorrect values for x or y substituted into the equations Page 29 (c) 20 Marks (10,10) (i) Att 3,3 Write as a single fraction x 3x . 2 8 (ii) Solve the equation 3(2x – 7) –5(x – 1) = 0. Verify your answer. c (i) 10 marks x 3x 4 x 3x 7 x 2 8 8 8 8 * or or etc → 7 marks * + and stops →4 Marks * x 3x 2 8 = →0 Marks Blunders (-3) B1 Correct answer without work B2 Incorrect common denominator and continues B3 Incorrect numerator from candidate's denominator B4 Omitted or incorrect denominator Slips (-1) S1 Numerical errors to a max of -3 Attempts (3 marks) A1 Any correct step. A2 Any correct common denominator found Worthless (0 marks) and stops W1 ( W2 Incorrect answer, with no work Page 30 Att3 c(ii) 10 marks Solve 3(2x – 7) –5(x – 1) = 0 6x -21 -5x + 5 = 0 x - 16 = 0 x = 16 Att 3 Verify 3(2x – 7) –5(x – 1) 3(2(16)– 7) –5(16 – 1 3( 32-7) – 5(15) 3(25) – 75 = 0 *Stops after correct removal of brackets 4 Marks *If changes -5 to +5 at the start: blunder (-3) *States x=16 (no work) and verifies correctly 7 Marks *States x=16 (no work) with no verification 4 Marks *Verifies correctly x=16 (not stated) Att 3 Blunders (-3) B1 Correct answer without work B2 Error(s) in distribution (each time) B3 Combining unlike terms (each time) and continues B4 Fails to group like terms B5 Error(s) in transposition (each time) B6 Fails to finish B7 Fails to verify Slips (-1) S1 Numerical errors to a max of -3 S2 Incorrect or no conclusion from their work Misreadings (-1) M1 3(2x+7) or similar and continues but see 2nd* above Attempts (3 marks) A1 Any one term correctly multiplied A2 Any correct step Worthless (0) W1 combining unlike terms before attempting multiplication and stops e.g. 3(14x) = 42x W2 Invented answer verified but see * above W3 Incorrect answer with no work Page 31 QUESTION 6 Part (a) Part (b) Part (c) 10(5,5) marks 30 (15,15 ) marks 10 (5,5) marks (a) 6. 10(5,5) marks (a) Att 2,2 Att (5,5) Att (2,2) Att 2,2 P = {(1, a), (2, a), (3, b), (4, c)}. Write out the domain and range of P. Domain = Range = (a) Domain 5 marks Att 2 Domain = {1, 2, 3,4} Slips (-1) S1 Each incorrect element omitted / included other than the misreading below. Misreadings (-1) M1 Correct range { a, b, c } or { a, a, b, c } given. Worthless (0) W1 No element of the domain appears. (a) Range 5 marks Range = { a, b, c } *Accept { a, a, b, c } for full marks. Slips (-1) S1 Each incorrect element omitted / included other then the misreading below Misreadings (-1) M1 Correct domain {1, 2, 3, 4} given Worthless (0) W1 No element of the range appears. Page 32 Att 2 Part (b) 30(15, 15) marks Att (5, 5) Draw the graph of the function f : x 5 2x x2 in the domain 2 x 4 , where x R . Table 15marks Att 5 f ( x) 5 2 x x 2 f (2) 5 2(2) (2) 2 f (1) 5 2(1) (1) 2 f (0) 5 2(0) (0) 2 f (1) 5 2(1) (1) 2 f (2) 5 2(2) (2) 2 f (3) 5 2(3) (3) 2 f (4) 5 2(4) (4) 2 = = = = = = = (2,3) 2 (1,2) 5 (0, 5) 6 (1 , 6) 5 (2 , 5) 2 (3 , 2) 3 (4 , -3). 544 = 3 5 2 1 500 5 2 1 544 569 5 8 16 = = = = = = OR A f (2) = 5 2(2) - (2) 2 = -3 f (1) = 5 2(1) - (1) 2 = 2 f (0) = 5 2(0) - (0) 2 = 5 f (1) = 5 2(1) - (1) 2 = 6 f (2) = 5 2(2) - (2) 2 = 5 f (3) = 5 2(3) - (3) 2 = 2 f (4) = 5 2(4) - (4) 2 = -3 B x 5 2x x 2 f (x) -2 5 -1 5 0 5 1 5 2 5 3 5 4 5 -4 -4 -2 -1 0 0 +2 -1 +4 -4 +6 -9 +8 -16 -3 2 5 6 5 2 -3 *Error(s) in each row/column calculation attracts a maximum deduction of 3 marks Blunders (-3) B1 Correct answer, without work i.e. 7 correct couples only and no graph B2 “+2 x ” taken as “2” all the way. [In the row headed “+2 x ” by candidate] B3 “5” calculated as “5 x ” all the way. [In the row headed “5” by candidate] B4 Adds in top row when evaluating f (x) in B. B5 Omits “5” row B6 Omits “+2 x ” row B7 Omits a value in the domain (each time). B8 Each incorrect image without work i.e. calculation through the function method (A) B9 Misreads “ x 2 ” as “ x 2 ” and places “ x 2 ” in the table or function. Slips (-1) S1 Numerical errors to a max of -3 in any row / column Page 33 Misreadings (-1) M1 Misreads “ 2 x ” as “ 2 x ” and places “ 2 x ” in the table or function. M2 Misreads “5” as “-5” and places “-5” in the table or function. Attempts (5 marks) A1 Omits “ x 2 ” row from table or treats “ x 2 ” as x or 2 x . A2 Any effort at calculating point(s). A3 Only one point calculated and stops. Graph 15 marks Att 5 5 4 3 2 1 -2 -1 1 2 3 4 -1 -2 -3 * * * Only one correct point graphed correctly Att 5 + Att 5 Correct graph but no table full marks i.e. (15 + 15) marks. Accept reversed co-ordinates if (i) if axes not labelled or (ii) if axes are reversed to compensate (see B1 below) Blunders ( -3) B1 Reversed co-ordinates plotted against non-reversed axes (once only) {See 3rd * above}. B2 Scale error (once only) B3 Points not joined or joined in incorrect order (once only) Slips (-1) S1 Each point of candidate graphed incorrectly {Tolerance 0.25 } S2 Each point (7 points needed ) from table not graphed [ See 2nd * above ] Attempts (5 marks) A1 Graduated axes (need not be labelled) A2 Some effort to plot a point { See 1st * above} Page 34 Part (c) (c) (i) (ii) 10 (5, 5) marks Draw the axis of symmetry of the graph you have drawn in 6(b). Att 2, 2 Use your graph to estimate the value of 5 2 x x 2 when x 1 5 . (c) (i) (c) (i) 5 marks Draw the axis of symmetry of the graph you have drawn in 6(b). Att 2 Axis of Symmetry: x = 1 f(1.5) = 5.5 5 4 3 2 1 -2 -1 1 2 3 4 -1 -2 -3 * Accept any vertical line (parallel to candidate’s y-axis) within tolerance of 0.25 . Blunders ( -3) B1 Any vertical line ( parallel to the candidate’s y-axis) outside of the tolerance. B2 Marks x 1 on the x-axis and stops. B3 States x 1 but no line is indicated on the graph. Attempts ( 2 marks) A1 Any attempt at axial symmetry of f (x) . A2 y-axis indicated as the axis of symmetry (See B1). Page 35 (c) (ii) (c) 5 marks Att 2 (ii) Use your graph to estimate the value of 5 2 x x 2 when x 1.5 Work to be shown on the graph and answer to be written here. 5.75 *Correct answer (clearly consistent with candidate’s graph) inside the tolerance without graphical indication 2 marks. Blunders (-3) B1 Correct answer without work B2 Answer on the diagram but outside of tolerance ( 0.25 ) B3 Fails to write down the answer, when indicated correctly on graph Slips (-1) S1 Correct answer indicated and/or written on graph only Attempts (2 marks) A1 Attempts at algebraic evaluation or calculator A2 Marks 1.5 in any way on either axis and stops Worthless (0) W1 Answer outside of tolerance without graphical indication. Page 36 Coimisiún na Scrúduithe Stáit State Examination Commission Scrúdu an Teastais Shóisearaigh JUNIOR CERTIFICATE EXAMINATION 2011 MARKING SCHEME MATHEMATICS ORDINARY LEVEL PAPER 1 Page 1 GENERAL GUIDELINES FOR EXAMINERS 1. Penalties of three types are applied to candidates’ work as follows: Blunders - mathematical errors/omissions (-3) Slips- numerical errors (-1) Misreadings (provided task is not oversimplified) (-1). Frequently occurring errors to which these penalties must be applied are listed in the scheme. They are labelled: B1, B2, B3,…, S1, S2,…, M1, M2,…etc. These lists are not exhaustive. 2. When awarding attempt marks, e.g. Att(3), note that any correct, relevant step in a part of a question merits at least the attempt mark for that part if deductions result in a mark which is lower than the attempt mark, then the attempt mark must be awarded a mark between zero and the attempt mark is never awarded. 3. Worthless work is awarded zero marks. Some examples of such work are listed in the scheme and they are labelled as W1, W2,…etc. 4. The phrase “hit or miss” means that partial marks are not awarded – the candidate receives all of the relevant marks or none. 5. The phrase “and stops” means that no more work is shown by the candidate. 6. Special notes relating to the marking of a particular part of a question are indicated by an asterisk. These notes immediately follow the box containing the relevant solution. 7. The sample solutions for each question are not intended to be exhaustive lists – there may be other correct solutions. 8. Unless otherwise indicated in the scheme, accept the best of two or more attempts – even when attempts have been cancelled. 9. The same error in the same section of a question is penalised once only. 10. Particular cases, verifications and answers derived from diagrams (unless requested) qualify for attempt marks at most. 11. A serious blunder, omission or misreading results in the attempt mark at most. 12. Do not penalise the use of a comma for a decimal point, e.g. €5.50 may be written as €5,50. Page 2 BONUS MARKS FOR ANSWERING THROUGH IRISH Bonus marks are applied separately to each paper as follows: If the mark achieved is 225 or less, the bonus is 5% of the mark obtained, rounded down. (e.g. 198 marks 5% = 9.9 bonus = 9 marks.) If the mark awarded is above 225, the following table applies: Bunmharc Marc Bónais Bunmharc Marc Bónais (Marks obtained) (Bonus Mark) (Marks obtained) (Bonus Mark) 226 11 261 – 266 5 227 – 233 10 267 – 273 4 234 – 240 9 274 – 280 3 241 – 246 8 281 – 286 2 247 – 253 7 287 – 293 1 254 – 260 6 294 – 300 0 Page 3 QUESTION 1 Part (a) Part (b) Part (c) 15 (10,5) marks 20 (5,5,5,5) marks 15 (5,5,5) marks (a) 10,5 marks (i) (ii) (a) S = Write down a subset of S that has one element. Write down a subset of S that has three elements. Att (3,2) Att (2,2,2,2) Att (2,2,2) Att 3,2 (a) (i) 10 marks {w} or {x} or {y} or {z} * No penalty for the omission of brackets. * No penalty for use of Venn Diagram to show subsets. Blunders (-3) B1 Any incorrect set of elements of S other than the misreading as below. Att 3 Misreadings (-1) M1 Subset of S with two or three elements. e.g. S = {w, x}. Attempts (3 marks) A1 Draws a single bracket & stops. A2 { } Null set or set itself Worthless(0) W1 No relevant element listed without brackets but see A1 above (a) (ii) {w,x, y} * * or {w, x, z } 5 marks or {w ,y, z} or No penalty for omission of brackets. No penalty for use of Venn Diagram to show subsets. Blunders (-3) B1 Any incorrect set of elements of S other than the misreading as below. Misreadings (-1) M1 Correct subsets of S with one or two elements e.g. S = {w,x }.etc Attempts (2) A1 Draws a single bracket & stops. A2 { } Null set or set itself Worthless(0) W1 No relevant element listed without brackets but see A1 above Page 4 Att2 {x, y,z} (b) 5,5,5,5 marks Att 2,2,2,2 U U is the universal set. P P = {2, 6, 9} Q = {1, 3, 5, 6} R = {3, 4, 6, 7, 9} 2 1 9 4 8 6 3 5 7 List the elements of: (i) R \ Q (ii) P΄, the complement of set P (iii) Q P R (iv) Q R \ P (i) R \ Q = {4,7,9} 5 marks Att 2 Blunders (-3) B1 Any incorrect set of elements of Q and R other than the misreading below. Misreadings (-1) M1 Q \ R = {1,5} Attempts (2 marks) A1 4 or 7 or 9 appear in the answer. A2 P Q / R ={ } Worthless(0) W1 {8} (ii) 5 marks Att 2 P΄, the complement of set P = {1,3,4,5,7,8} Blunders (-3) B1 Any incorrect set of the elements of P and Q and R other than the misreading below Misreadings (-1) M1 P Q R giving { 1,2,3,4,5,6,7,9 } (all needed) M2 R΄ = {2,1,5,8} M3 Q΄ giving {2,4,7,8,9 } M4 {2,6,9} Attempts (2 marks) A1 At least one correct entry appears in the answer Page 5 (iii) 5 marks Q P R {1,3,5,6,9} Blunders (-3) B1 Any incorrect set of elements of Q, P or R other than the misreadings below. Att 2 Misreadings (-1) M1 Q \ P R 1, 5, 3 . M2 Q P R {6} M3 Q P R {1,2,3,4,5,6,7,9} M4 Q P R {3,6} Attempts (2 marks) A1 1,3,5,6, or 9 appear in the answer. but see Misreadings above Worthless(0) W1 Answer {8}. (iv) 5 marks Att2 Q R \ P= {3} Blunders (-3) B1 Any incorrect set of elements of P and Q and R other than the misreading as below. B2 (Q ∩ R) = {6,3} and stops Misreadings (-1) M1 Q \ R P 1, 3, 5 . M2 Q \ ( R P) {1,5} M3 Q ( R / P) {1,3,4,5,7} Attempts (2 marks) A1 6 or 3 appear in the answer. Worthless(0) W1 Answer {8}. (c) 5,5,10 marks (i) List all the divisors of 18 and 24. (ii) Write down the highest common factor of 18 and 24. (iii) {5, 7, 9, 11, 13, 15} is the set of odd numbers between 4 and 16. Which of these numbers are not prime numbers? Give a reason for your answer. (i) 5 marks Divisors of 18: = 1, 2 ,3, 6, 9, 18 Divisors of 24: = 1,2, 3, 4, 6, 8, 12, 24 Slips (-1) S1 Each missing or incorrect element to a max of −3 Attempts (2 marks) A1 Any one correct element identified Worthless(0) W1 Elements listed that are not divisors of 18 or 24 Page 6 Att 2,2,3 Att 2 (ii) 5 marks Att 2 Highest common factor = 6 *Accept candidate’s answer from c(i) Blunders (-3) B1 A common factor that is not the highest Slips (-1) S1 Answer written as 2 3 Misreadings (-1) M1 Writes down LCM = 72 Attempts (2 marks) A1 Any common factor listed Worthless(0) W1 Incorrect answer without work but see M1 or * above (iii) 5 marks Not prime numbers: 9 and 15 Reason: “ Each has more than 2 factors” Blunders (-3) B1 Each incorrect or omitted entry Slips (-1) S1 No or incorrect reason given Misreadings (-1) M1 Gives prime numbers only Attempts (2 marks) A1 Any one relevant entry between 4 and 16 inclusive A2 Correct reason as to why numbers are not primes Worthless(0) W1 Incorrect answer with no work shown Page 7 Att 2 QUESTION 2 Part (a) Part (b) Part (c) (a) 10 marks 20(10,5,5) marks 20(5,5,5,5) marks 10 marks Att 3 Att (3,2,2) Att (2,2,2,2) Att 3 €52 is divided between Fiona and Orla in the ratio 9:4. How much does each receive? (a) 9+4= 13 52 13 4 9×4 =36 4×4 =16 10 marks OR 9+4 =13 OR 9x : 4x =4 x=4 = 36 4x=16 = 16 Orla: 16 or Fiona: 36 Att 3 13x = 52 52–36 =16 9x = 36 * Correct answer without work 7 marks * Incorrect answer without work 0 marks, except for answers given in A4 below * = 13 and = 5.777…/ 5.78 or 5.8 merits 4 marks Blunders (-3) B1 Divisor ≠ 13 and continues B2 Incorrect multiplier or fails to multiply (each time) B3 Adds instead of subtracts i.e. 36 + 52 = 98 B4 Fails to find second amount B6 Error in transposition Slips (-1) S1 Numerical errors where work is clearly shown to a max of −3 Attempts (3 marks) A1 Divisor 13 e.g, A2 A3 A4 A5 A6 and/ or and stops Indicates 13 parts or 9 parts or 4 parts or or and stops Indicates multiplication of 52by 9 and/or 4 and stops Both answers added together equal 52 (no work shown) Finds 9% of 52 (4.68) and 4% of 52 (2.08) One correct answer without work Worthless(0) W1 52 +9 = 61 or similar W2 Incorrect answer without work. (subject to A4) Page 8 (b) (i) 10,5,5 marks Att 3,2,2 By rounding each of these numbers to the nearest whole number, estimate the value of 14 18 4 086 . 1 96 (ii) Using a calculator, or otherwise, find the exact value of 14 18 4 086 1 96 (iii) Find the difference between the exact value in (ii) and the estimated value in (i). (i) 10 marks Att3 14 18 4 086 14 4 10 5 2 2 1 96 * * * and stops 7 marks. = and stops 7 marks.(-3) No penalty if the intermediate step between approximations and correct final answer is not shown i.e. not shown . . * Special Case: = 5.15 in this part Attempt 3 marks. (or or 5 ) . Blunders (-3) B1 Error(s) in rounding off to the nearest whole number (once only if consistent) B2 Decimal error in calculation of final value B3 An arithmetic operation other than indicated e.g. 14 – (4 ÷ 2) = 7 (breaking order) B4 Error(s) in the manipulation of the denominator e.g. or B5 Incorrect cancellation Slips (-1) S1 Numerical errors to a max of −3 Attempts (3 marks) A1 Only one approximation made to the given numbers and stops A2 Ans. 5 with no preceding rounding off Worthless (0) W1 Incorrect answer without work but note Special Case * above Page 9 (ii) 5 marks Att2 14 18 4 086 10 094 5 15 1 96 1 96 Blunders (-3) B1 B2 Decimal error or early rounding off . Leaves as B3 Treats as 14.18 – 4.086/1.96 . = 12.09530612 Treats as 14.18 + 4.086 = 9.319387753 1.96 B5 Treats as 14.18 – 4.086 = 3.148603878 1.96 Slips (-1) S1 Numerical errors to a max of −3 B4 Attempts (2 marks) A1 Any correct relevant calculation and stops. A2 Any of the following; (see above) 12.09530612, 9.319387753 or 3.148603878 merits 2 marks (minimum 4 decimal places) (with or without work) Worthless (0) W1 Incorrect answer without work but see A2 (iii) 5 marks 5·15-5 = 0·15 * Allow candidate’s previous answers Blunders (-3) B1 Correct answer without work B2 Decimal error (once only if consistent) B3 Finds the sum of b(i) and (ii) Attempts (2 marks) A1 Any relevant step i.e. transfers answers from b(i) and/or b(ii) Worthless (0) W1 Incorrect answer without work Page 10 Att2 (c) 5,5,5,5 marks (i) (ii) Att 2,2,2,2 Write (a3 )2 in the form an, n ℕ Using your answer from (i) or otherwise evaluate (53 )2. Before going on holidays to the USA Seán changed €500 into dollars. The exchange rate was €1 = US$1‧22. (iii) How many dollars did Seán get? (iv) When Seán came home he changed US$50 back into euro (€). The exchange rate was the same. How much, in euro, did Seán receive? Give your answer to the nearest cent. (i) 5 marks 3 2 3×2 6 3 2 = a or (a ) = a3×a3 = a6 (a ) = a or a a a a a = a6 * a a a a a and stops 4 marks * a3×2 and stops 4 marks * 6 only written down 2 marks Blunders (-3) B1 a3 = a a a and stops B2 each error in calculation involving indices e.g. (a3 )2 = a5 B3 Each incorrect number of a’s in the extended form Slips (-1) S1 Numerical errors to a max of −3 Attempts (2 marks) A1 (a3 )2 = a3+2 and stops A2 Some correct manipulation of indices Worthless (0) W1 Writes a only (ii) 5 marks (53 )2= 5 6 = 15625 or 53 = 125 1252 =15625 * Accept candidate’s answer fom c(i) unless it oversimplifies the question Blunders (-3) B1 Correct answer, without work B2 Each error in calculation involving indices B3 Each incorrect number of 5’s in the extended form B4 Fails to finish Slips (-1) S1 Numerical errors to a max of −3 Attempts (2 marks) A1 Some correct manipulation of indices A2 52 = 25 and stops A3 53 = 125 and stops A4 Candidate transfers answer from c(i) Worthless(0) W1 Incorrect answer with no work shown Page 11 Att 2 Att 2 (iii) * 5 marks Att 2 €500 × 1‧22 = $610 No penalty for omission of € or $ signs Blunders (-3) B1 Correct answer, without work B2 Incorrect operator i.e. divides by 1.22 correctly : 409.836 B3 Decimal error B4 Fails to finish i.e. €500 × 1‧ 22 and stops Slips (-1) S1 Numerical errors to a max of −3 Attempts (2 marks) A1 Some correct manipulation of 500 and/ or 1.22 Worthless(0) W1 Incorrect answer with no work shown (iv) 5 marks 50 40 9836 40 98 1 22 Blunders (-3) B1 Correct answer, without work B2 Multiplies by 1.22 `i.e. 50 × 1.22 = 61 . B3 Incorrect ratio i.e. or B4 Decimal error B5 Fails to finish i.e. leaves answer as . Slips (-1) S1 Numerical errors to a max of −3 S2 Fails to round off or rounds off incorrectly Attempts (2 marks) A1 Some manipulation of 50 and/ or 1.22 A2 If answer is 41 or 40.9 with no work shown but see W1 Worthless(0) W1 Incorrect answer with no work shown but see A2 Page 12 Att 2 QUESTION 3 Part (a) Part (b) Part (c) 15 marks 15 (5,5,5) marks 20 (5,5, 5,5) marks (a) Att 5 Att (2,2,2) Att (2,2,2,2) 10 marks Att 3 Three books were bought. They cost €8·75, €9·50 and €10·55 respectively. If a €50 note was used to pay for the books, how much change was given? Part (a) 15 marks €8.75 + €9.50 + €10.55 = €28.80 €50.00 - €28.80 = €21.20 Change = €21.20 Att 5 €50.00 – (€8.75 + €9.50 + €10.55) or 50.00 – €8.75 - €9.50 - €10.50 = €21.20 Change = €21.20 *Accept 2120 or 21.2. *No penalty for the omission of the € sign *Final subtraction step subject to maximum deduction of −3. Blunders (-3) B1 Correct answer without work 12 marks B2 Fails to find the change. B3 Operation other than addition when finding the total cost. B4 Operation other than subtraction when finding the change. B5 Each missing addition. B6 Decimal error eg. €2.12 (Note 1st * above). Slips (−1) S1 Numerical errors to a max of 3 Attempts (3 marks) A1 Any attempt at addition or subtraction of the given numbers and stops Worthless (0) W1 Incorrect answer without work is 0 marks. W2 Multiplication or division of the given numbers. Page 13 (b) (i) (i) 5,5,5 marks Att 2,2,2 A washing machine costs €320 plus VAT at 21·0%. Calculate the total cost of the washing machine after the VAT is added. (ii) A popular breakfast cereal comes in two sizes of packet, Regular (360 g) and Large (900 g). A standard portion of cereal is 30 g. How many portions are there in each size of packet? (iii) A Regular box costs €0‧96 and a Large box costs €2‧25. Using the number of portions per box, or otherwise, find which size is better value? 5 marks 100% 1% = 121% Total Bill = = 320 320 100 = 21% = × 320 VAT = × 320 Att 2 320 x 1.21 Total Bill = € 387.20 x 121 = 3.2 x 121 €387.20 = 67.2 Total Bill = 320 + 67.2 Total Bill = €387.20 * 320 + 21% = 387.20 5 marks. * 320 x 21% = 67.2 and stops 2 marks. * 320 + 21% and stops or 320 × 21% and stops 2 marks. * €67.20 without work and stops merits 2 marks. Blunders (-3) B1 Correct answer without work B2 Decimal error. B3 Inverts as 100 or 100 and continues (giving answers 264.46 or 1523.81). 121 21 B4 Mishandles 121% or 21% eg. 320 × 121 or 320 ÷ 121 or similar. (Note: 320 must be used) B5 320 taken as 121% or 21%. B6 No addition of VAT (as per candidates work). B7 Subtraction of VAT (as per candidates work). Slips (-1) S1 Numerical errors to a max of 3. Attempts (3 marks) A1 121 or 21 or 320 and stops. 100 100 100 A2 100% = 320 and stops. A3 100 × 121 and stops. 320 A4 320 or similar and stops. 121 Worthless (0) W1 Incorrect answer without work W2 320 + 21 = 341 and stops or continues. Page 14 (ii) 5 marks Att 2 Regular: Number of portions = 360/30 =12 Large: Number of portions = 900/30 = 30 Blunders (-3) B1 B2 B3 B4 Correct answers without work Multiplication instead of division when finding the number of portions (once only) Finds only one answer Decimal error Slips (-1) S1 Numerical errors to a max of −3 Attempts (2 marks) A1 Any attempt at division and stops A2 30 + 30 + …or any correct step Worthless (0) W1 Incorrect answer without work Page 15 b (iii) 5 marks Att 2 Method 1 Regular: 96 ÷ 12 = 8c per portion Large: 225 ÷ 30 = 7.5c per portion Large box is better value. Method 2 Regular: 360g = 96cent Large: 900g = 225 c 1g = 96 1g = 225 360 900 1g = 0.267cent 1g = 0.25cent Large box is better value. Method 3 Regular: 96cent = 360g Large: 225cent = 900g 1 cent = 360 1 cent = 96 1 cent = 3.75g 1 cent = 4g Large box is better value Method 4 Regular: 10 boxes = 3600g = 10 x 0.96 = 9.60 Large: 4 boxes = 3600g = 4 x 2.25 = 9.00 Large box is better value. * Candidate must indicate in some way that the Large box is better value. See S2. * Accept candidate’s previous answer Blunders (-3) B1 Operation other than division in unitary methods 1, 2, and 3 B2 Operation other than multiplication in common denominator method 4 B3 Finds unit cost or weight for one size box only B4 Decimal error Slips (-1) S1 Numerical errors to a max of −3 S2 Fails to highlight or indicate Large box as better value Misreading (-1) M1 Transposes costs or weight for each box (eg. Regular box costs €2.25 or similar) and continues. Attempt (2 marks) A1 States Larger box without any relevant supporting work. A2 Some attempt at division or multiplication using either €0.96 or €2.25. A3 Some attempt at division using 12 or 30 or 360 or 900 A4 12 and 30 or 360 and 900 both multiplied as alternative in method 4 Worthless (0) W1 Incorrect answer without work W2 Adds given figures Page 16 (c) 5,5,5,5 marks Att 2,2,2,2 Geraldine’s annual wage is €40 000. She pays income tax at the rate of 20% on the first €33 000 of her wage and income tax at the rate of 41% on the remainder of her wage. Geraldine has an annual tax credit of €3500. (i) Calculate the tax on the first €33 000 of her wage, at the rate of 20%. (ii) How much of Geraldine’s wage is taxed at the rate of 41%? (iii) Calculate the amount of tax payable at the rate of 41%. (iv) Calculate the tax due. (i) 5 marks 100% = 33000 1% = 330 20% = 6600 Tax = €6600 * Tax = 33000 × 20 100 Tax = €6600 Att 2 Tax = 33000 × 0.2 20% = 1 5 Tax = €6600 33000 ÷ 5 Tax = €6600 No penalty for omitting € symbol Blunders (-3) B1 Correct answer without work. B2 Mishandles 20% eg. 33000 × 20 = 660000 or 33000 ÷ 20 = 1650 B3 Uses € 40000 instead of €33000 B4 Decimal error. Slips (-1) S1 Numerical error to a max of −3. Attempts (2 marks) A1 Some use of 100 in attempt to find percentage eg. 20% = A2 Writes 33000 × 20 and stops Worthless (0) W1 Incorrect answer without work W2 33000 + 20 and stops or continues Page 17 or 0.2 or and stops 3(c) (ii) (c) (ii) How much of Geraldine’s wage is taxed at the rate of 41%? 5 marks Att 2 €40000 – €33000 = €7000 taxed at 41% * No penalty for omitting € symbol Blunders (-3) B1 Correct answer without work. B2 Operation other than subtraction used with €40000 or €33000 B3 €6600 or 3500 is used in a subtraction with €40000 or €33000. . Slips (-1) S1 Numerical error to a max of −3. Attempts (2 marks) A1 Some subtraction involving €40000 or €33000. Worthless (0) W1 Incorrect answer without work. (c) (iii) 5 marks 100% = 7000 1% = 70 41% = 2870 Tax = €2870 Tax = 7000 × 41 100 Tax = €2870 Att 2 Tax = 7000 × 0.41 Tax = €2870 * No penalty for omitting € symbol *Accept use of candidate’s answer from (ii) above. Blunders (-3) B1 Correct answer without work. B2 Mishandles 41% eg. 7000 ÷ 41 = 170.73 or similar. Note: (No penalty if already penalised in (c) (i).... consistent error.) B3 Does not use €7000 but see 2nd * above. B4 Decimal error. Slips (-1) S1 Numerical error to a max of –3. Attempts (2 marks) A1 Some correct use of 100 in attempt to find percentage eg. 41% = or 0.41 and stop A2 Some correct use of €7000 A3 Uses €40000 or €33000 instead of €7000. Worthless (0) W1 Incorrect answer without work W2 7000 + 41 = 7041 and stops or continues Page 18 (iv) 5 marks €6,600 + €2870 = €9470 * * * €9470 - €3500 = €5970 Total Tax €9470 Tax Credit €3500 Tax Due €5970 No penalty for omitting € symbol Accept use of candidate’s answer from (i) and (iii) above. If all 3 boxes are correctly filled in award full marks Blunders (-3) B1 Correct answer without work. B2 Subtracts to find gross tax. e.g. 6600 – 2870 = 3730. B3 Misuse or no use of Tax Credit B4 Decimal error B5 Total tax incorrectly calculated Slips (-1) S1 Numerical error to a max of –3. Attempts (2 marks) A1 Answer from c (i) or (iii) written in this part. Worthless (0) W1 Incorrect answer without work. Page 19 Att 2 QUESTION 4 Part (a) 15(10,5) marks Part (b) 15(5,10) marks Part (c) 20(5,5,10) marks (a) 10,5 marks If a = 4, find the value of: (i) 3a + 5 (ii) 3a2 – 20 (i) 10 marks (i) 3a + 5 3(4) + 5 = 12 + 5 = 17 * 12 +5 9 marks Blunders (-3) B1 Correct answer, without work B2 Leaves 3(4) in the answer B3 Incorrect substitution and continues B4 Breaks order i.e. 3(4+5) = 3(9) = 27 B5 Treats 3(4) as 7 or 34 Slips (-1) S1 Numerical errors to a max of 3 S2 Treats as 3a – 5 S3 Fails to finish Misreadings (-1) M1 Uses 5a + 3 Attempts (2 marks) A1 Any number substituted for a and stops e.g. 3(6) A2 Any correct step A 3 Treats as 15a = 15(4) = 60 or 8a =8(4) = 32 Worthless (0) W1 Incorrect answer with no work Page 20 Att (3,2) Att (2, 3) Att (2,2,3) Att 3,2 Att 3 (a)(ii) * 2 3a – 20 48 -20 5 marks 3(4) – 20 = 3(16) – 20 = 48 – 20 = 28 2 4 marks Blunders (-3) B1 Correct answer without work B2 Leaves 42 in the answer B3 Incorrect substitution and continues B4 Breaks order e.g. 3(16 – 20) = 3( –4 ) = –12. B5 Treats 3(16) as 3 + 16 B6 Incorrect squaring eg. 42 = 8 B7 Treats as a2 – 20 i.e omits the 3 Slips (-1) S1 Numerical errors to a max of −3 S2 Fails to finish but see * above Misreadings (-1) 2 M1 Treats as 3a +20 Attempts (2 marks) A1 A3 2 Any substitution for a and stops Any correct step Worthless (0) W1 Incorrect answer, with no work Page 21 Att2 (b) 5,10 marks (i) x 5x . 3 6 Multiply (2x – 5) by (3x – 4) and write your answer in its simplest form. Write as a single fraction (ii) (i) 5 marks = 0 Marks, but allow * or or 5Marks + and stops 5 Marks Blunders (-3) B1 Correct answer without work B2 Incorrect common denominator and continues B3 Incorrect numerator from candidate's denominator B4 Omitting denominator Slips (-1) S1 Drops denominator S2 Numerical errors to a max of 3 Attempts (2 marks) A1 Any correct step. A2 Any correct common denominator found Worthless (0) W1 ( and stops W2 Att 2 x 5x 2x 5x 7 x 6 3 6 6 * * Att 2,3 Incorrect answer, with no work Page 22 or etc for full marks b(ii) 10 marks (2x – 5) (3x – 4) = 2x(3x – 4) – 5(3x – 4) = 6x2 – 8x – 15x + 20 = 6x2– 23x + 20 * If 6x2 – 8x – 15x + 20 is correct (minimum 7 MARKS) Blunders (-3) B1 Correct answer without work B2 Error in distribution each time B3 Errors in multiplication of powers B4 Errors in collecting like terms B5 Mathematical (sign ) errors eg –5 × –4 = – 20 B6 (2x – 5) written as (2x + 5 ) and continues and/or (3x – 4) written as (3x +4) --oversimplifies Slips (-1) S1 Numerical errors to a max of −3 Misreadings (-1) M1 (5x–2)(4x–3) etc and continues Attempts (3 marks) A1 One term correctly multiplied and stops e.g. 6x2 A2 2x(3x–4) or –5(3x–4) and stops A3 2x(3x – 4) –5(3x – 4) and stops Worthless (0) W1 Incorrect answer with no work Page 23 Att 3 (c) (i) (ii) 5,10,10 marks Att 2,3,3 The cost of a DVD is €x. The cost of a CD is €3 less. What is the cost of a CD in terms of x? The total cost of 3 DVDs and 2 CDs is €54. Write an equation in x to represent this information. Solve your equation to find the cost of a DVD. c(i) 5 marks CD : x –3 * Algebraic work required to earn marks Blunders (-3) B1 Incorrect expression for the cost of a CD other than misreading below Misreadings (-1) M1 Answer given as 3+x or 3–x Attempts (2 marks) Worthless (0) W1 Cost of CD given as a constant or x. Page 24 Att 2 (ii) 5 marks Equation : 3x + 2(x – 3) =54 3x + 2x – 6 = 54 5x = 60 x = 12 Cost of a DVD = 12 * B1 B2 B3 B4 B5 Att 2 Accept candidates answer from previous work. Error in forming equation. Distribution error Transposition error Stops at 5x = 60 or fails to solve equation Error in collecting like terms Misreading (-1) M1 2x + 3(x – 3) = 54 or similar Slips (-1) S1 Numerical errors to a max of −3 Attempts (2 marks) A1 Answer from part c (i) written down and stops. A2 Any effort at forming an expression. A3 Writes x = 12 A4 Any effort at solving their equation A5 Successful Trial and Error Worthless (0) W1 Incorrect answer with no work. Page 25 (iii) 10 marks Att 3 10 marks Att 3 Solve for x and y: x + 3y = 12 3x + 2y = 11 (iii) 5x + 3y = 12 (× –2) OR 5x + 3y = 12 (× 3) 3x + 2y = 11 (×3) 3x+2y =11 (× –5) OR x = 3( ) +2y =11 –10 x – 6y = –24 9x + 6y = 33 –x = 9 x = –9 5(– 9) + 3y = 12 – 45 + 3y = 12 3y = 57 15x +9y =36 −15x −10y=−55 −y = −19 y =19 5x +3(19) =12 5x +57 =12 5x =12 – 57 36 -9y +10y = 55 y =55 − 36 y = 19 x= x= x= y= 19 x = –9 x = −9 5x = −45 x = −9 * Apply only one blunder deduction (B2 or B3) to any error(s) in establishing the first equation; in terms of x only or the first equation in terms of y only. * Finding the second variable is subject to a maximum deduction of (3). Blunders (-3) B1 Correct answers without work (stated or substituted) B2 Error or errors in establishing the first equation in terms of x only (–x = 9) or the first equation in terms of y only (–y = –19) through elimination by cancellation (but see S1) B3 Error or errors in establishing the first equation in terms of x only (x = –9) or the first equation in terms of y only (–y = –19) through elimination by substitution (but see S1) B4 Errors in transposition when finding the first variable B5 Errors in transposition when finding the second variable B6 Incorrect substitution when finding second variable B7 Finds one variable only Slips (-1) S1 Numerical errors to a max of –3 Attempt (3 marks) A1 Attempt at transposition and stops A2 Multiplies either equation by some number and stops A3 Incorrect value of x or y substituted correctly to find candidate’s correct 2nd variable Worthless (0) W1 Incorrect values for x or y substituted into the equations Page 26 QUESTION 5 Part (a) Part (b) Part (c) (a) (a) 10 marks 20(5,5,5,5) marks 20(10,10) marks 10 marks Att 3 Att (2,2,2,2) Att (3,3) Att 3 Write in its simplest form 2( x + 5) + 7( 2x + 3). (a) 10 marks Att 3 2( x + 5) + 7( 2x + 3) = 2x +10 +14x +21 = 16x + 31 *Stops after correct removal of brackets 7 Marks Blunders (-3) B1 B2 B3 B4 B5 Correct answer without work Error(s) in distribution (each time) Combining unlike terms after removal of brackets and continues Fails to group like terms Fails to finish Slips (-1) S1 Numerical errors to a max of –3 Misreadings (-1) M1 2(x + 2) and continues. Attempts (3 marks) A1 Any one term correctly multiplied A2 Combines unlike terms at the start and finishes correctly Worthless (0) W1 Combining unlike terms before attempting multiplication and stops e.g. 2(5x) = 10x Page 27 (b) 5,5,5,5 marks Att 2,2,2,2 Factorise: (i) (ii) (iii) (iv) 4xy – 8y xy – xz + 3y – 3z x² + 7x +12 x² – 64 (i) 5 marks Att 2 4xy – 8y = 4y(x – 2) * y(4x–8) or 2y(2x–4) or 2(2xy –4y) or 4(xy – 2y) merit 4 Marks Blunders (-3) B1 Removes factor incorrectly Attempts (2 marks) A1 Indication of common factor e.g. underlines y’s and stops A2 Lists factors of 4 and factors of 8 (ii) 5 marks xy – xz + 3y – 3z = x(y – z) + 3(y – z) or = ( y − z )(x + 3) Att 2 y(x + 3) – z(x + 3) = ( y − z )(x + 3) * Accept also (with or without brackets) for 5 marks any of the following (y−z) and (x+3) [The word and is written down.] (y−z) or (x+3) [The word or is written down.] (y−z), (x+3) [A comma is used] Blunders (-3) B1 Correct answer without work B2 Stops after first line of correct factorisation. e.g. x(y–z) +3 (y–z) or equivalent. B3 Error(s) in factorising any pair of terms B4 Correct first line of factorisation but ends as (x+3).–yz or equivalent Slips (-1) S1 (y–z) (x+3) Attempts (2 marks) A1 Pairing off, or indication of common factors and stops A2 Correctly factorises any pair and stops Page 28 (iii) x2 + 7x + 12 x2 + 4x + 3x + 12 x(x + 4) +3(x + 2) (x + 3)(x +4) 5 marks Att 2 7 x +3 x +4 (x + 3)(x +4) 7 4112 21 2 7 49 48 7 1 2 2 6 8 3 and 4 2 2 (x + 3)(x + 4) Factor Method Blunders (-3) B1 Incorrect two term linear factors of x2+7x+12 formed from correct (but inapplicable) factors of x 2 and/or ±12. e.g. (x+12)(x−1) B2 Incorrect factors of x 2 and/or ±12 B3 Correct cross method but factors not shown and stops B4 x(x+3)+4(x+3)or similar and stops Slips (-1) S1 Numerical errors to a max of 3 Attempts (2 marks) A1 Some effort at factorization e.g. (x )( ) or the cross with at least one “x” written in A2 States one correct factor without work Worthless (0 marks) W1 x2 + 7x = 12 or similar and stops W2 Incorrect Trial and error W3 Oversimplification, resulting in a linear equation W4 Combines x with numbers and continues or stops Formula Method Blunders (-3) B1 Error in a,b,c substitution (apply once only) B2 Sign error in substituted formula (apply once only) B3 Error in square root or square root ignored 7 1 B4 Stops at 2 B5 Incorrect quadratic formula and continues B6 No factors from roots or incorrect factors Slips (-1) S1 Numerical errors to a max of −3 S3 One factor only Attempts (2 marks) A1 Correct formula and stops Worthless (0 marks) W1 Combines x with numbers and continues or stops Page 29 (iv) 5 marks x² – 64 = x² – (8)2 Att 2 = (x+ 8)(x – 8) * Accept also (with or without brackets) for 5 marks any of the following x + 8 and (x–8) [The word and is written down.] (x+8) or (x−8) [The word or is written down.] (x+8) , (x−8) [A comma is used] * Quadratic equation formula method is subject to slips and blunders. * (x−√64)(x+√64) merits 5 marks * x±8 merits 4 marks Blunders (-3) B1 Incorrect two term linear factors of x2–64 formed from correct (but inapplicable) factors of x 2 and 64 e.g ( x 64)( x 1) B2 Incorrect factors of −64 B3 Incorrect factors of x 2 B4 (8 − x)(8 + x). B5 (x − 64)(x + 64) B6 Answer left as roots. (x = ±8) Slips (-1) S1 x−8(x+8) Attempts (2 marks) A1 Some effort at factorization e.g. (x )( ) or the cross with at least one “x” written in A2 8 appears 2 A3 x – 64 =x.x – 8.8 only A4 Mention of the difference of two squares .e.g. x2 – 642 A5 Correct quadratic equation formula quoted and stops A6 √64 Worthless (0) W1 Combines xs to “numbers” and continues or stops Page 30 (c) 10,10 marks 5(3x + 1) – 2(5x + 35) = 0. (i) Solve the equation Verify your answer. (ii) Solve x2 + 3x – 10 = 0. (i) 10 marks Att 3,3 Att 3 5(3x + 1) – 2(5x + 35) = 0 15x + 5 – 10x – 70 = 0 5x – 65 = 0 5x = 65 x = 13 Verify * * * * 5(3x + 1) – 2(5x + 35) x = 13 5(3(13) + 1) – 2(5(13) + 35) 5(39 + 1) – 2(65 + 35) 5(40) – 2(100) 200 – 200 = 0 If changes −2 to +2 at the start: Blunder(−3) States x =13 (no work) and verifies correctly 7 Marks States x =13 (no work) with no verification 4 Marks Verifies correctly x = 13 (not stated) Att 3 Blunders (-3) B1 Correct answer without work B2 Error(s) in distribution (each time) B3 Combining unlike terms (each time) and continues B4 Fails to group like terms B5 Error(s) in transposition (each time) B6 Fails to finish B7 Fails to verify or verifies incorrectly Slips (-1) S1 Numerical errors to a max of –3 Misreadings (-1) M1 5(3x−1) or similar and continues but see * above Attempts (3 marks) A1 Any one term correctly multiplied A2 Any correct step Worthless (0) W1 combining unlike terms before attempting multiplication and stops e.g. 5(4x) = 20x W2 Invented answer verified but see * above W3 Incorrect answer with no work Page 31 (ii) x2 + 3x – 10 = 0 x2 + 5x – 2x – 10 = 0 x(x + 5) – 2x – 10 = 0 x(x + 5) – 2(x + 5) = 0 (x + 5)(x – 2) = 0 (x + 5) = 0 or (x – 2) = 0 10 marks (x + 5)(x -2) = 0 (x + 5) = 0 or (x – 2) = 0 x = -5 x = -5 or x=2 x +5 x 2 or x=2 Att 3 3 3 41 10 21 2 3 9 40 37 2 2 10 4 5 and 2 2 2 * 2 correct solutions by Trial and Error 10 Marks * 1 correct solution by Trial and Error 3 Marks (Attempt) Factor Method Blunders (-3) B1 Correct answers without work B2 Incorrect two term linear factors of x2+3x –10 formed from correct (but inapplicable) factors of x2 and/or ±10,e.g. (x + 10)(x – 1) B3 No roots given. (once only) B4 Incorrect factors of x2 and/or ±10 B5 Correct cross method but factors not shown and stops [Note: B3 applies also]. B6 x(x+5)−2(x+5) or similar and stops [Note: B3 applies also]. B7 Error(s) in transposition Slips (-1) S1 Numerical errors to a max of –3 S2 One root only from factors Attempts (3 marks) A1 Some effort at factorization e.g. (x )( ) or the cross with at least one “x” written in A2 States one correct root without work Worthless (0) W1 x2 +3x = 10 or similar and stops W2 Incorrect Trial and error W3 Oversimplification, resulting in a linear equation Formula Method Blunders (-3) B1 Error in a,b,c substitution (apply once only) B2 Sign error in substituted formula (apply once only) B3 Error in square root or square root ignored B4 Stops at B5 Incorrect quadratic formula and continues Slips (-1) S1 Numerical errors to a max of −3 p S2 Roots left in the form q S3 One root only Attempts (3 marks) A1 Correct formula and stops A2 One correct substitution and stops Page 32 QUESTION 6 Part (a) Part (b) Part (c) 15(5,10) marks 20 (10,10) marks 15 (5,5,5) marks (a) Att (2,3) Att (3,3) Att (2,2,2) 5, 10 marks (a) f (x) = 2x – 7. (i) Find: f(4) (ii) f(–3) (a) 5 marks (i) f (x) = 2x – 7 f (4) = 2(4) – 7 = 8 – 7 = 1 Blunders (-3) B1 B2 Correct answer without work. Mathematical error. e.g. 2 4 24, B3 Leaves 2(4) in the answer. B4 Combines “ x' s ” to “numbers” and continues e.g. 2 x 7 5 x 5( 4) 20 . B5 Mathematical error e.g 8 7 1 . B6 Breaks order i.e. 2( 4 7 ) 2( 3) 6 . Slips (-1) S1 Numerical errors to a max of −3. S2 Leaves x in the answer e.g. 1x Misreadings (-1) M1 Correctly substitutes in any number other than 4 and continues. Attempts (2marks) A1 Treats as equation and continues or stops. . i.e 2 x 7 4 . A2 Substitutes for “ x ” and stops. i.e. 2(4). Worthless (0) W1 Combines “ x' s ” to “numbers” and stops. 2 7 5 . W2 Ignores x giving W3 4[ f ( x)] 8 x 28 . W4 Replaces coefficient i.e. 2 x 4 x . W5 Incorrect answer without work. Page 33 Att 2,3 Att2 (a) (ii) (a) (ii) 10 marks Att3 f ( 3) 2( 3) 7 = 6 7 = 13 Blunders (-3) B1 Correct answer without work. [Do not penalise if already penalised in part (a) (i) or work is shown in part (a) (i).] B2 Mathematical error. i.e. −6 – 7 = 13 B3 Leaves 2(−3) in the answer. B4 Combines “x’s” to “numbers” and continues e.g. 2 x 7 5 x 5( 3) 15 . B5 Breaks order i.e. 2(–3 –7) = 2(–10) = –20 Slips (-1) S1 Numerical errors to a max of –3. S2 Leaves x in the answer e.g. −13 x Misreadings (-1) M1 Substitutes in any negative number other than −3 and continues. Attempts (3marks) A1 Treats as equation and continues or stops. i.e. 2 x 7 3 . A2 Substitutes in any positive number A3 Substitutes for x and stops. i.e. 2(−3). Worthless (0) W1 Ignores x giving 2 7 = −5 W2 −3f(x) = −6x + 21 W3 Combines “x’s” to “numbers” and stops. W4 Replaces coefficient i.e. 2 x 3x . W5 Incorrect answer without work. Page 34 (b) 10 (Table), 10 (Graph) marks Draw the graph of the function Att 3,3 g : x 2x² – 4x + 1 in the domain 1 x 3, where x ℝ. (b) 10 marks ( table ) Att 3 g : x 2x² – 4x + 1 g(x) =2x² – 4x + 1 g(–1) =2(–1) ² – 4(–1) + 1 = 2 + 4 +1 = 7 g(0) =2(0) ² – 4(0) + 1 = 0 + 0 +1 = 1 g(1) =2(1) ² – 4(1) + 1 = 2 – 4 +1 = – 1 g(2) =2(2) ² – 4(2) + 1 = 8 – 8 +1 = 1 g(3) =2(3) ² – 4(3) + 1 = 18 – 12 +1 = 1 Table A 10 marks Att 3 B f (1) = 2 (1)2 -4(-1) +1 = 7 f (0) = 2 (0)2 -4(0) +1 = 1 f (1) * (–1,7) (0, 1) (1, – 1) (2, 1) (3, 7) x 2x 2 -1 2 0 0 1 2 2 8 3 18 = 2 (1)2 f ( 2) = 2 (2)2 -4(1) +1 = -1 -4(2) +1 = 1 4x +1 +4 +1 -0 +1 -4 +1 -8 +1 - 12 +1 f (3) -4(3) +1 = 7 f (x ) 7 1 -1 1 7 = 2 (3)2 Error(s) in each row/column calculation attracts a maximum deduction of 3marks Blunders (-3) B1 Correct answer, without work i.e. 5 correct couples only and no graph B2 Takes “ 2x 2 ” as “ x 2 ” and places “ x 2 ” in the table or function. B3 Errors in evaluating “ 2x 2 ”, e.g. 2(1)2 (2)2 4 , once only if consistent. B4 “–4 x ” taken as “–4” all the way [In the row headed “-4 x ” by candidate] B5 “+1” calculated as “+1 x ” all the way. [In the row headed “+1” by candidate] B6 Adds in top row when evaluating f (x ) in table method (B). B7 Omits “+1” row B8 Omits “–4 x ” row B9 Omits a value in the domain (each time). B10 Each incorrect image, without work, or, calculation through the function method (A). Page 35 Slips (-1) S1 Numerical errors to a max of –3 in any row / column S2 Fails to find a value of Range each time in table to a max of 3 Misreadings (-1) M1 Misreads “ 4 x ” as “ 4 x ” and places “ 4 x ” in the table or function. M2 Misreads “+1” as “–1” and places “–1” in the table or function. Attempts (3marks) A1 Omits “ 2x 2 ” row or treats “ 2x 2 ” as 2 x or x , (i.e. evaluates a linear function) A2 Any effort at calculating point(s) in the Domain A3 Only one point calculated and stops. (b) 10 marks (graph) Att 3 7 6 5 4 3 2 1 -1 1 2 3 -1 * * * * Accept candidates values from previous work ( 5 co-ordinates needed ) but see S2 Only one correct point graphed correctly Att 3 + Att 3 Correct graph but no table full marks i.e. (10 + 10) marks. Accept reversed co-ordinates if (i) if axes not labelled or (ii) if axes are reversed to compensate (see B1 below) Page 36 Blunders ( -3) B1 Reversed co-ordinates plotted against non-reversed axes (once only) {See 4th * above}. B2 Scale error (once only) B3 Points not joined or joined in incorrect order (once only). Slips (-1) S1 Each point of candidate graphed incorrectly. {Tolerance 0.25 } S2 Each point { 5 points needed } from table not graphed [ See 2nd * above ] Attempts (3 marks) A1 Graduated axes (need not be labelled) A2 Some effort at plotting a point { See 2nd * above} (c) (c) 5,5,5 marks Att 2,2,2 Given that y = x – 1, complete the table below. (i) x y 1 2 3 4 On the grid below the graph of the line y = 3 – x is drawn. Using your answers from (i), draw the graph of y = x – 1 on the same grid. 4 3 y=3–x 2 1 -1 1 2 -1 Page 37 3 4 5 (iii) Use the graphs drawn in 6(c) (ii) to write down the co-ordinates of the point of intersection of the two lines y = 3 – x and y = x – 1. Answer to be written here. (c) 5 marks (i) Att 2 Given that y = x – 1, complete the table below. x y 1 0 2 1 3 2 4 3 * Accept candidate’s values without work Slips (-1) S1 Each ‘ y ’ value omitted or incorrect. Misreadings (-1) M1 Treats y x 1 as y x 1 . (consistent error) Attempts (2) marks) A1 Any one correct ‘ y ’ value. A2 Any effort at calculating points. A3 Treats as y = –x and continues Worthless (0) W1 Copies x values into y row. W2 All ‘ y ’ values incorrect with no work shown but (See M1 and A3 above) Page 38 (ii) 5 marks Att 2 On the grid below the graph of the line y = 3 – x is drawn. Using your answers from (i), draw the graph of y = x – 1 on the same grid. 4 3 y=3–x 2 1 -1 1 2 -1 * Accept candidates values from previous work Blunders ( -3) B1 Reversed co-ordinates plotted. B2 Points not joined or joined in incorrect order. Slips (-1) S1 Each point of candidate graphed incorrectly. {See B1}. S2 Each point from table not graphed. Attempts (2 marks) A1 Any one correct point plotted. A2 Any incorrect straight line drawn Worthless (0) W1 No correct point plotted. {See B1 above}. Page 39 3 4 5 (iii) 5 marks (2,1) * Accept correct answer based on candidate’s graph from c(ii), otherwise, attempt marks at most. Blunders (-3) B1 Answer beyond tolerance ( 0.25 ). B2 Answer given with co-ordinates reversed, i.e. ( y , x ) . Slips (-1) S1 Correct answer written on graph but not presented in the answer box. Attempts (2 marks) A1 Algebraic evaluation. (fully correct) A2 Point of intersection clearly indicated correctly on graph, but not written down. Worthless (0) W1 Answer outside of tolerance without graphical indication. W2 Incorrect answer from candidate’s graph. Page 40 Att 2 JUNIOR CERTIFICATE EXAMINATION 2010 MARKING SCHEME MATHEMATICS ORDINARY LEVEL PAPER 1 GENERAL GUIDELINES FOR EXAMINERS 1. Penalties of three types are applied to candidates’ work as follows: • Blunders - mathematical errors/omissions (-3) • Slips- numerical errors (-1) • Misreadings (provided task is not oversimplified) (-1). Frequently occurring errors to which these penalties must be applied are listed in the scheme. They are labelled: B1, B2, B3,…, S1, S2,…, M1, M2,…etc. These lists are not exhaustive. 2. When awarding attempt marks, e.g. Att(3), note that • any correct, relevant step in a part of a question merits at least the attempt mark for that part • if deductions result in a mark which is lower than the attempt mark, then the attempt mark must be awarded • a mark between zero and the attempt mark is never awarded. 3. Worthless work is awarded zero marks. Some examples of such work are listed in the scheme and they are labelled as W1, W2,…etc. 4. The phrase “hit or miss” means that partial marks are not awarded – the candidate receives all of the relevant marks or none. 5. The phrase “and stops” means that no more work is shown by the candidate. 6. Special notes relating to the marking of a particular part of a question are indicated by an asterisk. These notes immediately follow the box containing the relevant solution. 7. The sample solutions for each question are not intended to be exhaustive lists – there may be other correct solutions. 8. Unless otherwise indicated in the scheme, accept the best of two or more attempts – even when attempts have been cancelled. 9. The same error in the same section of a question is penalised once only. 10. Particular cases, verifications and answers derived from diagrams (unless requested) qualify for attempt marks at most. 11. A serious blunder, omission or misreading results in the attempt mark at most. 12. Do not penalise the use of a comma for a decimal point, e.g. €5.50 may be written as €5,50. Page 1 QUESTION 1 Part (a) Part (b) Part (c) Part (a) (i) (ii) 10(5, 5) marks 25(10, 5, 5, 5) marks 15(5, 5, 5) marks Att(2, 2) Att(3, 2, 2, 2) Att(2, 2, 2) 10(5, 5) marks Att (2, 2) Using the Venn diagram below, shade in the region that represents A∩B. Using the Venn diagram below, shade in the region that represents A \ B A (a)(i) B 5 marks A B Att 2 A B Blunders (-3) B1 Any incorrect indication other than the misreading below Misreadings (-1) M1 A ∪ B indicated. Worthless(0) W1 No filling in of the Venn Diagram (a)(ii) A/B 5 marks A Att 2 B Blunders (-3) B1 Any incorrect indication other than misreading below Misreadings (-1) M1 B/A indicated Worthless(0) W1 No filling in of the Venn diagram Page 2 Part (b) U is the universal set 25(10, 5, 5, 5) P P = {2, 4, 6, 8, 10, 12} 10 2 Q = {3, 6, 9, 11, 12} 4 1 R = {4, 8, 11, 12} Att(3, 2, 2, 2) 3 6 8 5 12 9 Q 11 R (b)(i) (i) List the elements of P ∩ Q ∩ R . 10 marks Att 3 (b)(i) 10 marks Att 3 P ∩ Q ∩ R = {12} Blunders (-3) B1 Any incorrect set of the elements of P and Q and R other than the misreading below Misreadings (-1) M1 P ∪ Q ∪ R giving {2,3,4,6,8,9,10,11,12} (all needed) Attempts (3 marks) A1 1 or 5 appear in the answer (b)(ii) 5 marks (ii) List the elements of R', the complement of the set R. (ii) R' = {1, 2, 3, 5, 6, 9, 10} Blunders (-3) B1 Any incorrect set of elements of R' other than the misreadings below. Misreadings (-1) M1 R\Q giving {4, 8}, R\P giving {11}, R\(P ∪ Q) giving { } M2 P' = {3, 9, 11, 5} or Q' = {1, 2, 4, 5, 8, 10} Attempts (2 marks) A1 1,2,3,5,6,9, or 10 appear in the answer. A2 R or any proper subset of R. Page 3 Att 2 . (b) (iii) (iii) 5 marks Att 2 List the elements of P\ ( Q ∩ R ) . (iii) P\ ( Q ∩ R ) = {2, 4, 6, 8, 10} Blunders (-3) B1 Any incorrect set of elements of P and Q and R other than the misreadings below Misreadings (-1) M1 P\(Q ∪ R) giving {2,10} or (Q ∩ R)\ P giving {11} Attempts (2 marks) A1 1 or 5 appear in the answer (b) (iv) 5 marks Att 2 (iv) Write down # (Q ∪R). (iv) #(Q ∪R) = 7 Blunders (-3) B1 Any incorrect cardinal number (Q ∪R) ≤11 other than the misreadings as below Misreadings (-1) M1 Q ∪ R giving {3,4,6,8,9,11,12} M2 #(Q ∪ R)' = 4 M3 #(Q∩R) = 2 Attempts (2 marks) A1 Some understanding of notation e.g. Cardinal numbers or number of elements Worthless (0) W1 Any number greater than 11 Page 4 (c) 15(5, 5, 5) marks Att(2, 2, 2) In a survey, a group of 72 students were asked if they played basketball or tennis 37 of these students said they played basketball (B) 30 of these students said they played tennis (T) 28 of these students said they played basketball but not tennis (c)(i) 5 marks (i) Represent this information in the Venn diagram below. (c)(i) 5 marks B Att2 Att2 T 28 9 21 14 Blunders (-3) B1 Each incorrect or omitted entry but see S1 and M1 below Slips (-1) S1 Numerical errors, where work is clearly shown, to a max of 3 Misreadings (-1) M1 Interchanges Basketball and Tennis Attempts (2 marks) A1 Any one relevant entry A2 #B = 37 or #T = 30 or #U = 72 (c)(ii) 5 marks Att2 (ii) How many students played neither basketball nor tennis? (c)(ii) 5 marks Att2 c(ii) 28+21+9 = 58 72-58 =14 * Any correct answer written here in the space provided takes precedence over an incorrect Venn diagram (Subject to S1) * Accept candidate’s work from previous part c(i) Blunders (-3) B1 Any incorrect use of the given numbers or the numbers from an incorrect Venn diagram (Subject to S1) Slips (-1) S1 Numerical errors where work is clearly shown, to a max of 3 Attempts (2 marks) A1 Any one relevant sum where work is clearly shown Worthless (0) W1 Incorrect answer with no work shown Page 5 (c)(iii) 5 marks (iii) What percentage of the students surveyed played both basketball and tennis? Att2 (c)(iii) Att2 * * 5 marks 9 × 100 = 12.5% 72 or 100 = 12.5% 8 Any correct answer written here in the space provided takes precedence over an incorrect Venn diagram (Subject to S1) Accept candidate’s work from previous part c(i) Blunders (-3) B1 Any incorrect use of the given numbers or the numbers from an incorrect Venn diagram (Subject to S1) B2 Correct answer without work Slips (-1) S1 Numerical errors, where work is clearly shown, to a max of 3 Attempts (2 marks) A1 Mention of 9 or candidate’s work from c(i) A2 Some use of 100 Worthless (0) W1 Incorrect answer with no work shown Page 6 QUESTION 2 Part (a) Part (b) Part (c) Part (a) 10 marks 25(10, 5, 10)marks 15(5, 5, 5)marks 10 marks There is €1200 in a prize fund. The first prize is Find the value of the first prize. (a) Method (1) 10 =1200 10 1 1200 = =120 10 10 7 =120 × 7=840 10 = €840 Att 3 Att(3, 2, 3) Att(2, 2,2) Att 3 7 of the fund. 10 10 marks Att 3 Method (2) Method (3) Method (4) 10 parts=1200 1200 ×7 10 10 parts=1200 120 × 7 3 parts=120 × 3=360 1 part= 1200 =120 10 7 parts=120 × 7 €840 = €840 7 parts=1200-360 = € 840 Correct answer without work ⇒ 7 marks 1200 × 10 = 1714.28 ⇒ 7 marks * Special Case 7 1200 * Stops at or 120 ⇒ 4 marks 10 * Stops at 1200 ×7[= 8400] ⇒ 4 marks * Incorrect answer without work ⇒ 0 marks, except for answers given in A2 below Blunders (-3) B1 Divisor ≠ 10 and continues but see 2nd * B2 Incorrect multiplier i.e. ≠ 7 and continues but see 2nd * 3 B3 Gets of 1200 only 10 B4 Decimal error (once only) B5 Fails to finish Slips (-1) S1 Numerical errors where work is clearly shown to a max of 3 Attempts (3 marks) 10 1 3 A1 Indicates 0.7, or 7: 10, or , or , or , or .3 only, and stops 10 10 10 A2 120 or 8400 or 360 or 1714.29 only, appears (no work shown) 1200 A3 or 1200 × 10 and stops 7 A4 1200 is multiplied or divided by any wrong number correctly * Worthless(0) W1 1200 +7 = 1207 or similar Page 7 Part (b) 25(10, 5, 10) marks Att (3, 2, 3) (i) By rounding each of these numbers to the nearest whole number, 9 ⋅15 × 2 ⋅196 5 ⋅ 5815 estimate the value of 9 ⋅15 × 2 ⋅196 5 ⋅ 5815 (ii) Using a calculator, or otherwise, find the exact value of 3 9 (iii) Using a calculator, or otherwise, write and as decimals. 8 25 Hence, or otherwise, put the following numbers in order, starting with the smallest And finishing with the largest 3 9 , , 0.37 8 25 Part (b)(i) 10 marks Att 3 9 ⋅15 × 2 ⋅196 is approximately equal to: 5 ⋅ 5815 9 × 6 2 18 = = 3 6 9 × 2 and stops ⇒ 7 marks. 6 * No penalty if the intermediate step between approximations and correct final answer is not 18 shown i.e. not shown 6 9 ⋅15 × 2 ⋅196 18 3 * Special Case: = 3.6 or 3 in this part ⇒ Attempt 3 marks. 5 ⋅ 5815 5 5 18 * and stops ⇒ 7 marks.(-3) 6 Blunders (-3) B1 Error(s) in rounding off to the nearest whole number (once only if consistent) B2 Decimal error in calculation of final value B3 An arithmetic operation other than indicated 9 2 18 B4 Error(s) in the manipulation of the denominator e.g. × = 6 6 36 B5 Incorrect cancellation Slips (-1) S1 Numerical errors to a max of 3 Attempts (3 marks) A1 Only one approximation made to the given numbers and stops A2 Ans. 3 with no preceding rounding off Worthless (0) * Page 8 W1 Incorrect answer without work (b)(ii) 9.15 × 2.196 = 20.0934 ÷ 5.5815 = 3.6 or 5 marks 18 or 5 or 9.15 × 2.196 5.5815 20.0934 ⇒ =3.6 5.5815 Att 2 Blunders (-3) B1 Decimal error or early rounding off 9.15 2.196 B2 Treats as × = 1.639344262 × 0.393492623=0.644987906 5.5815 5.5815 9.15 − 2.196 6,954 B3 Reads as = =1.245901639 5.5815 5.5815 9.15 + 2.195 B4 Reads as =2.032786885 5.5815 5,5815 5.5815 B5 Treats as = =0.27777777… 9.15 × 2.196 20.0934 5.5815 5.5815 = =0.491935483 B6 Treats as 9.15 + 2.196 11.346 5.5815 5.5815 B7 Treats as = =0.802631578 9.15 − 2.195 6.954 20.0934 B8 Leaves as 5,5815 Slips (-1) S1 Numerical errors to a max of 3 Attempts (2 marks) A1 Any correct relevant calculation and stops. 9.15 2.196 =1.639344262 or =0.393442623 e.g. 9.15 × 2.196=20.0934 or 5.5815 5.5815 A2 Any of the following; (see above) 0.644987906 , 1.245901639, 2.032786885 0.27777777…, 0.491935483 or 0.802631578 merit 2 marks (minimum 4 decimal (with or without work) places) Worthless (0) W1 Incorrect answer without work but see A2 Page 9 (b)(iii) 10marks 3 = 0.375 8 9 25 * Accept: * Note: Att 3 9 = 0.36 25 3 8 0.37 0.36, 0.37, 0.375 for 10 marks. 3 9 = 0,375 or = 0.36 merits 4 marks 25 8 Blunders (-3) B1 Fails to write a fraction as a decimal (each time) B2 Writes fraction as incorrect decimal (each time) B3 Decimal error (once only if consistent) B4 Inverts fraction and continues. (each time) B5 Incorrect order or fails to order Attempts (3 marks) 37 A1 and stops 0.37 = 100 A2 Attempt at ordering using all 3 given numbers A3 Any 2 of the given numbers in the correct order i.e.( Worthless (0) W1 Nothing correct 0.37 0.37 W2 or or similar 8 25 Page 10 9 9 3 3 , 0.37 ), ( 0.37, ), ( , ) 25 25 8 8 Part(c) 15(5, 5, 5) (i) Using a calculator, or otherwise, divide 1120 by 0∙035. Express your answer in the form a × 10 n , where 1 ≤ a < 10 and n ∈ N Att(2, 2, 2) a5 × a 2 , Give your answer in the form a n , where n ∈N 3 a×a 65 × 6 2 (iii) Using your answer to part (ii), or otherwise, find the value of 6 × 63 (ii) Simplify (c)(i) * 5 marks Att2 1120 = 32000 0.035 = 3.2 × 3.2 × ( without work) 4 marks Blunders (-3) B1 Decimal error B2 B3 0.035 =0.00003125 1120 Multiplies fraction i.e. 1120 × 0.035=39.2 (3.92 × 10) Inverts fraction Slips (-1) S1 Numerical errors to a max of 3 S2 Incorrect format, where a < 1 or a ≥ 10 S3 32000 and stops S4 Error in index when forming Scientific Notation Attempts (2 marks) A1 A2 A3 Any relevant step. e.g. Partial long division e.g. 1 = 1000 0.035 35 1120000 35 = 200 7 Page 11 1120 =3 0.0355 (c)(ii) 5 marks . a × a 2 a.a.a.a.a.a.a = = a.a.a = a3 3 a×a a.a.a.a 5 2 a ×a a7 = = a 7-4 = a 3 or 3 4 a×a a Att2 5 or a5 × a 2 1 = a 4 × = a3 3 a×a a a × a × a (as answer) ⇒ 4 marks a7 * and stops ⇒ 2 marks a4 a 7 and stops ⇒ 2 marks * a 3 × a and stops ⇒ 2marks * Blunders (-3) * B1 Correct answer, without work B2 Each error in calculation involving indices B3 Each incorrect number of a’s in the extended form B4 Each incorrect elimination of a’s in the extended form Slips (-1) a7 1 S1 = 3 or −3 as final answer 4 a a Attempts (2 marks) A1 Some correct manipulation of indices Worthless(0) W1 Incorrect answer with no work shown (c)(iii) 5 marks 5 or or 2 6 ×6 = 63 =216 or 3 6× 6 7776 × 36 279936 = = 216 6 × 216 1296 6.6.6.6.6.6.6 = 6.6.6 = 216 6.6.6.6 5 2 6 ×6 1 =64 × =63=216 3 6× 6 6 or 63=216 *Accept candidate’s answer from c(ii) unless it oversimplifies the question. Blunders (-3) B1 Correct answer, without work B2 Each error in calculation involving indices B3 Each incorrect number of 6’s in the extended form B4 Each incorrect elimination of 6’s in the extended form B5 Fails to finish Attempts (2 marks) A1 Some correct manipulation of indices A2 Writes answer from c(ii) in c(iii) Worthless(0) W1 Incorrect answer with no work shown Page 12 Att2 QUESTION 3 Part (a) Part (b) Part (c) 15 marks 20(10, 5, 5) marks 15(10, 5) marks Att 5 Att(3, 2, 2) Att(3, 2) Part (a) 15 marks Carol buys a magazine which costs €2·83. In her purse she only has the following Three 50 cent coins Four 20 cent coins Seven 10 cent coins How much money will she have left after paying for the magazine? Att 5 (a) Att 5 15 marks 50 × 3 = 150 20 × 4 = 80 10 × 7=70 Total amount (150+80+70) = 300 ⇒Change⇒ € 3.00 – €2.83 = €0.17 * * * Accept 17c, (€0.17) Final subtraction step subject to maximum deduction of 3 marks. No penalty for the omission of € symbol. Blunders (-3) B1 B2 B3 B4 B5 B6 B7 Correct answer without work Fails to find the change. Fails to find total cost i.e. no addition Operation other than subtraction when finding the change Operation other than addition when finding total cost Decimal error (Note: * above) Each missing multiplication or addition Slips (-1) S1 Numerical errors to a max of 3 Attempts (5 marks) A1 Any attempt at addition / subtraction /multiplication of the given numbers Worthless (0) W1 Incorrect answer without work Page 13 Part (b) 20(10, 5, 5) marks Att(3, 2, 2) (i) A bicycle costs €305. There is a 15% discount on the cost during a sale What is the sale price of the bicycle? (ii) David wishes to get some bars for a party A packet of 12 bars cost €4.08 in Shop A. A packet of 7 bars costs €2·17 in Shop B. Find the unit cost (cost of one bar) in each shop (iii) If David buys 84 bars, how much will he save by buying the bars in the shop offering the better value? (b)(i) 10 marks 305 × 15 = €45.75 100 100%-15% = 85% 305 − 45.75 = €259.25 305 × Att 3 305 × .85 = €259.25 85 = €259.25 100 * 305 – 15% = 259.25 10 marks * 305 × 15% = 45.75 and stops 7 marks * 305 – 15% and stops 4 marks or 305 × 15% and stops 4 marks * €45.75 without work and stops merits 4 marks Blunders (-3) B1 B2 B4 B5 Correct answer without work Decimal error 100 100 Inverts as or and continues (giving answers 358.82 or 2033.33 ) 85 15 Mishandles 85 % or 15% e.g. 305 × 85 or 305 ÷ 85 or similar Note: {305 must be used} 305 taken as 85%or15% B6 No subtraction (as per candidates work) B3 B7 Addition of discount ( as per candidates work) B8 305×1.15=€350.75 Slips (-1) S1 Numerical errors to a max of 3 Misreadings (-1) M1 Reads as €350 instead of €305 Attempts (3 marks) 15 85 305 A1 or or and stops 100 100 100 A2 100% = 305 and stops 85 A3 100× and stops 305 305 A4 or similar and stops 85 Worthless (0) W1 Incorrect answer without work W2 305-15 =290 and stops or continues Page 14 (b)(ii) 5 marks Shop A. unit cost 408 = €0.34 12 Shop B Unit cost 2.17 = €0.31 7 * Accept 34c and/or 31c Blunders (-3) B1 Correct answers without work. B2 Operation other than division when finding the unit cost (once only) B3 Finds only one unit cost B4 Decimal error Slips (-1) S1 Numerical errors to a max of 3 Attempts (2 marks) A1 Any attempt at division Worthless (0) W1 Incorrect answer without work W2 Addition or subtraction of the given numbers (b)(iii) 5 marks 34−31 = 3 84×34 = 2856 84 × 3=252 = €2.52 84×31 = 2604 Savings = 2856 − 2604 = 252 = €2.52 * Accept 2.52 or 252 or 252 c Blunders (-3) B1 B2 B3 B4 B5 Att 2 Correct answer without work Operation other than subtraction or multiplication where appropriate Finds only one unit saving Decimal error Fails to subtract Slips (-1) S1 Numerical errors to a max of 3 Attempts (2 marks) A1 Any attempt at subtraction or multiplication A2 Any one correct step Worthless (0) W1 Incorrect answer without work Page 15 Att 2 Part (c) 20(10, 10) marks Att(3, 3) (i) €12000 is invested at 2% per annum What is the amount of the investment at the end of the first year? (ii) Using central heating oil for 6 hours a day, a tank full of oil will last for 90 days If the oil were used for only 5 hours a day, how much longer would it last? (c)(i) 10 marks Att 3 €12000 is invested at 2%per annum. What is the amount of the investment at the end of the first year? (c)(i) 10 marks 12000 × 1.02 = €12240 or 12000 × 2 = €240 100 Att 3 12000 × 12000+240 = €12240 * * * * * * P×R 100 12000 = ×2 100 = €240 12000+240 = €12240 102 = €12240 100 Finds interest only, €240 and stops ⇒ 7 marks €240 without work and stops ⇒4 marks €12000 + 2% = €12240 ⇒ 10 marks €12000 × 2% = €240 and stops ⇒ 7 marks €12000 + 2% and stops ⇒ 4 marks €12000 × 2% and stops ⇒ 4 marks Blunders (-3) B1 Correct answer, without work B2 Mishandles 2% of 12,000. {Must use 12,000} B3 Decimal error B4 Fails to finish Slips (-1) S1 Numerical errors to a max of 3 Attempts (3 marks) A1 Some use of 100 in attempt to find percentage e.g. 2% = A2 Correct formula (with or without substitution) and stops Worthless (0) W1 Incorrect answer without work W2 12000+2 (=12002) and stops Page 16 2 and stops 100 I = (c)(ii) 5 marks Att2 Using central heating oil for 6 hours a day, a tank full of oil will last for 90 days If the oil were used for only 5 hours a day, how much longer would it last? (c)(ii) 5 marks 6 × 90 = 540 540 = 108 5 108-90 = 18 * * 6 : 5= x : 90 6-5 = 1 5x = 6(90) = 540 x =108 1 × 90 = 90 108-90=18 90 ÷ 5 = 18 90 = 18 att. only ⇒2 marks 5 Answer 108 (work shown) ⇒ 4 marks Answer Att2 i.e.(no mention of 6) Blunders (-3) B2 Adds instead of subtracts B3 Incorrect ratio B4 Incorrect division or similar B5 Fails to finish (method 3) Slips (-1) S1 Numerical errors to a max of 3 Attempts (2 marks) A1 Some indication of subtraction or ratio A2 Some correct use of 6 or 5 but see W2 A3 Answer 108 or 18 (no work shown) A4 6-5 [=1] Worthless (0) W1 Incorrect answer without work 90 W2 [=15] and stops 6 Page 17 QUESTION 4 Part (a) Part (b) Part (c) 10 marks 20(10, 10) marks 20(5, 5, 10) marks Part (a) 10(5, 5)marks Att(2, 2) Att(3, 3) Att(2, 2, 3) Att(2, 2) If a = 3 and b = 5, find the value of (i) (ii) a +2b ab − 6 (a)(i) * * 5 marks a + 2b =3+2(5) =3+10 =13 3+10 4 marks 5+2(3) = 5+6=11 4 marks Blunders (-3) B1 Correct answer, without work B2 Leaves 2(5), in the answer B3 Incorrect substitution and continues B4 Breaks order i.e. 3+2(5) = (5)(5) = 25 B5 Treats 2(5) as 7 or 25 Slips (-1) S1 Numerical errors to a max of 3 S2 Treats as a – 2b Misreadings (-1) M1 a and b interchanged see * above Attempts (2 marks) A1 Any number substituted for a or b and stops e.g. 2(8) A2 Writes 5 or 3 in this part A3 Any correct step Worthless (0) W1 Incorrect answer with no work Page 18 Att2 (a)(ii) 5 marks * ab − 6 3(5) − 6 = 15 − 6 =9 15 − 6 4 marks Blunders (-3) B1 Correct answer without work B2 Leaves 3(5) in the answer B3 Incorrect substitution and continues B4 Breaks order e.g. 3(5 − 6) B5 Treats 3(5) as 8 or 35 Slips (-1) S1 Numerical errors to a max of 3 S2 Treats as ab + 6 Misreadings (-1) M1 a and b interchanged but no penalty here if already penalised in a(i) Attempts (2 marks) A1 Any substitution for either a or b and stops A2 writes 5 or 3 in this part A3 Any correct step Worthless (0 marks) W1 Incorrect answer, with no work Page 19 Att2 Part (b) (i) (ii) 20(10, 10) marks Write in it’s simplest form (3x + 2y) −2(x + 3y −4) Solve 3x − 2≤7, x ∈ N (b)(i) 10 marks (i) * 3x + 2y −2x − 6y + 8 Att 3 (3x + 2y) −2(x + 3y −4) = 3x + 2y −2x − 6y + 8 = x − 4y + 8 Blunders (-3) (stops or continues) 7 marks (at least ) B1 Correct answer without work B2 Error in distributive law and continues (each time) B3 Fails to finish Slip (-1) S1 Numerical errors to a max of 3 Attempts (3 marks) A1 Any correct step. A2 Combines “x’s” to numbers and continues with any correct step Worthless (0 marks) W1 Combines “x’s” to numbers and stops W2 Incorrect answer, with no work Page 20 Att(3, 3) (b)(ii) 10 marks 3x −2≤7 ⇒ 3x≤7 + 2 ⇒ 3x≤9 ⇒ x≤3 {1, 2, 3} (not necessary) -5 * Att3 -4 -3 -2 -1 0 1 2 3 4 5 Do not penalize for inclusion of 0 in answer Blunders (-3) B1 Correct answer without work B2 Error in transposition B3 No plotting on number line B4 Mishandles the direction of inequality e.g. 3 x ≥ 9 B5 Treats inequality as equality and continues Slips (-1) S1 Numerical errors to a max of 3 S2 ≤ taken as < S3 Missing elements or incorrect elements on the number line (each time), but see S4 S4 Correct range but shaded in Misreadings (-1) M1 3 x + 2 ≤ 7 , and continues M2 x∈Z or x∈R correctly mapped Attempts (3 marks) A1 Attempt at transposition and stops A2 0 or 1 or 2 or 3 substituted for x A3 Number line drawn with one of the correct elements only clearly indicated A4 Combines “x's” to “numbers” e.g. x≤7 and continues Worthless (0) W1 Incorrect answer with no work e.g.{1,2,3,4,5,6,7,8,…..}. Page 21 Part (c) (i) (ii) 20(5, 5, 10) marks Eoin is t years of age Katie is 4 years older than Eoin Laura is twice as old as Eoin Write Katie’s age and Laura’s age in terms of t From part(i), the sum of Eoin’s age, Katie’s age and Laura’s age is 52 Write down an equation in t to represent this information Solve your equation to find Eoin’s age in years (iii) Solve for x and for y: (c)(i) Att(2, 2, 3) Katie’s age = t + 4 7x + 2y = 11 4x + y = 7 5 marks Att2 Laura’s age = 2t Blunders (-3) B1 Each incorrect expression Misreading (-1) M1 Substitutes x (or similar) for t M2 Treats Laura’s age as twice Katie’s age i.e. 2(t + 4) Attempts (2 marks) A1 Any attempt at forming an expression but numbers written on their own are worthless (c)(ii) 5marks t + t + 4 + 2t = 52 4t + 4=52 4t = 52−4 4t = 48 t = 12 i.e.( Eoin’s age = 12 ) (not necessary) * Accept candidates’ expression from previous work. Blunders (-3) B1 Correct answer without work (t = 12 stated or substituted) B2 Errors in transposition B3 Stops at 4t = 48 B4 error in forming equation B5 Fails to solve equation Slip (-1) S1 Numerical errors to a max of 3 S2 Leaves as 48 or similar 4 Attempts (2 marks) A1 Answer from part c(i) written down and stops A2 Any correct step Worthless (0 marks) W1 Incorrect answer, with no work Page 22 Att2 (c)(iii) Solve for x and y: * * Att3 10 marks Att3 7x + 2y = 11 4x + y = 7 (c)(iii) I 7x+ 7x +2y 2y ==1111 4x 4x++yy==77 7x +2y = 11 -8x 7x+ – 2y 2y==-14 11 -x –8x –2y==-3 –14 x ==3–3 –x 4(3)+y x = −=3 7= 3 12 + y−=1 7 y = 7-12 y y= =-5–5 10 marks I II 7x7x+ + 2y2y==1111 4x4x ++ y =y = 77 28x+8y = 44 -28x-7y 28x +8y==-49 44 –28x – 7y = – 49 y =y–5 = -5 4x-5 = 7 4x =7+5 4x = 12 x = x3 = 3 III II y =y 7– = 7-4x 4x 7x+2(7-4x) = 11 7x + 14-8x = 11 7x + 2(7– 4x) = 11 7x +-x14=–11-14 8x = 11 –x = –3 x = − 3-x==3-3 −1 x=3 y y==–5-5 Apply only one blunder deduction (B2 or B3) to any error(s) in establishing the first equation; in terms of x only or the first equation in terms of y only. Finding the second variable is subject to a maximum deduction of (−3). Blunders (-3) B1 Correct answers without work (stated or substituted) B2 Error or errors in establishing the first equation in terms of x only (-x = -3) or the first equation in terms of y only (y = –5) through elimination by cancellation (but see S1) B3 Error or errors in establishing the first equation in terms of x only (-x = -3) or the first equation in terms of y only (y = –5) through elimination by substitution (but see S1) B4 Errors in transposition when finding the first variable B5 Errors in transposition when finding the second variable B6 Incorrect substitution when finding second variable B7 Finds one variable only Slip (-1) S1 Numerical errors to a max of 3 Attempt (3 marks) A1 Attempt at transposition and stops A2 Multiplies either equation by some number and stops A3 Incorrect value of x or y substituted correctly to find his correct variable Worthless (0 marks) W1 Incorrect values for x or y substituted into the equations Page 23 QUESTION 5 Part (a) Part (b) Part (c) 10 marks 20(5, 5, 10) marks 20(5, 5, 10) marks Att 3 Att(2, 2, 3) Att(2, 2, 3) Part (a) 10 marks (a) Solve the equation 3(x −2) =2x + 5. Att 3 (a) Att 3 10 marks 3x − 6 = 2x + 5 3x −2x = 6 + 5 x =11 Blunders (-3) B1 Correct answer without work B2 Error(s) in distribution (each time) B3 Combining unlike terms (each time) and continues B4 Fails to group like terms B5 Error(s) in transposition (each time) B6 Fails to finish Slips (-1) S1 Numerical errors to a max of 3 Misreadings (-1) M1 3(x + 2) and continues. Attempts (3 marks) A1 Any correct multiplication. A2 Any correct step Worthless (0) W1 combining unlike terms before attempting multiplication and stops e.g. 3(-2x) = 2x + 5 Page 24 Part (b) 20(5, 5, 10) marks (i) Factorise −25 (ii) Factorise ab − 2ax + mb − 2mx (iii) Factorise + 4x − 12. Hence solve the equation + 4x −12 = 0. (b) (i) 5 marks Att(2, 2, 3) Att 2 2 x − 25 * * * x 2 − 52 (x − 5)(x + 5) Accept also (with or without brackets) for 5 marks any of the following (x − 5) and (x + 5) [The word and is written down.] (x − 5) or (x + 5) [The word or is written down.] (x − 5) , (x + 5) [A comma is used] Quadratic equation formula method is subject to slips and blunders. x − 25 x + 25 merits 5 marks ( )( ) Blunders (-3) B1 Incorrect two term linear factors of − 25 formed from correct (but inapplicable) factors of x 2 and ± 25 .e.g ( x − 25)( x + 1) B2 Incorrect factors of 25 B3 Incorrect factors of x 2 B4 (5 − x )(5 + x ) . B5 ( x − 25)( x + 25) . B6 Answer left as roots. (x = ±5 ) Slips (-1) S1 ( x − 5) ± ( x + 5) Attempts (2 marks) A1 Correct factors of x 2 only A2 Correct factors of ± 25 only A3 ± x or ± 5 appears. A4 x 2 − 25 = x × x − 5 × 5 A5 Mention of the difference of two squares .e.g. x 2 − 25 2 A6 Correct quadratic equation formula quoted and stops A7 25 Worthless (0 marks) W1 Combines xs to “numbers” and continues or stops Page 25 (b) (ii) * 5 marks ab −2ax + mb − 2mx b(a+ m) −2x(a+m) (a + m)(b −2x) ab −2ax + mb − 2mx a(b−2x)+ m(b−2x) (a + m)(b −2x) or Accept also (with or without brackets) for 5 marks any of the following (a+ m) and (b−2x) [The word and is written down.] (a+ m) or (b−2x) [The word or is written down.] (a+ m), (b−2x) [A comma is used] Blunders (-3) B1 B2 B3 B4 Att 2 Correct answer without work Stops after first line of correct factorisation. e.g. a(b − 2x) + m(b − 2x)or equivalent. Error(s) in factorising any pair of terms Correct first line of factorisation but ends as (a+ m).-2bx or equivalent Slips (-1) S1 (a + m) ± (b−2x) Attempts (2 marks) A1 Pairing off, or indication of common factors and stops A2 Correctly factorises any pair and stops (b) (iii) 10 marks Att 3 x 2 + 4 x − 12 = 0 x x 2 + 6 x − 2 x − 12 = 0 x(x + 6 ) − 2(x + 6 ) = 0 (x + 6)(x − 2) = 0 ⇒ x = −6 and x = 2 +6 x −2 ⇒ (x + 6 )(x − 2 ) = 0 ⇒ x = −6 and x = 2 * 2 correct roots without work or by substitution Page 26 − (4 ) ± (4)2 − 4(1)(− 12) 2(1) − 4 ±8 − 4 ± 16 + 48 = 2 2 4 − 12 = − 6 and =2 2 2 ⇒ x = −6 and x = 2 ⇒ (x + 6 )(x − 2 ) = 0 4 MARKS Blunders (-3) B1 B2 B3 B4 B5 B6 B7 Factor Method Correct answers without work Incorrect two term linear factors of + 4x−12 formed from correct (but inapplicable) factors of x 2 and/or ±12. e.g. (x + 12)(x − 1) No roots given. Incorrect factors of x 2 and/or ±12 Correct cross method but factors not shown and stops [Note: B3 applies also]. x(x+6)−2(x+6) or similar and stops [Note: B3 applies also]. Error(s) in transposition Slips (-1) S1 Numerical errors to a max of 3 S2 One root only Attempts (3 marks) A1 Some effort at factorisation A2 States one correct root without work Worthless (0 marks) W1 x 2 + 4 x = 12 or similar and stops W2 Incorrect Trial and error W3 Oversimplification, resulting in a linear equation Formula Method Blunders (-3) B1 Error in a,b,c substitution (apply once only) B2 Sign error in substituted formula (apply once only) B3 Error in square root or square root ignored −4±8 B4 Stops at 2 B5 Incorrect quadratic formula and continues B6 No factors from roots Slips (-1) S1 Numerical errors to a max of 3 p S2 Roots left in the form q S3 One root only Attempts (3 marks) A1 Correct formula and stops A2 One correct substitution and stops Page 27 Part (c) (i) (ii) 20(5, 5, 10) marks 5x − 1 4x − 9 + as a single fraction. 2 3 Give your answer in its simplest form. Express Verify your answer to part (i) by substituting x = 3 into and into your answer to part (i). (iii) (c)(i) (i) Att(2, 2, 3) 5x − 1 4 x − 9 + 2 3 Multiply ( x − 2) by ( −3x +11) Write your answer in its simplest form 5 marks 3(5 x − 1) + 2(4 x − 9) 6 23 x − 21 15 x − 3 + 8 x − 18 ⇒ = 6 6 Att2 5x − 1 4x − 9 9 x − 10 Zero marks + = 2 3 5 Blunders (-3) * B1 B2 B3 B4 Correct answer without work Error(s) in distribution e.g. 3(5 x − 1) =15 x −1 Mathematical error e.g. −3 −18= +21 Incorrect common denominator and continues B5 Incorrect numerator from candidate's denominator e.g. B6 B7 No simplification of numerator Omitting denominator Slips (-1) S1 S2 Drops denominator Numerical errors to a max of 3 S3 Answer not in simplest form. e.g. 46 x − 42 12 Attempts (2 marks) A1 6 only or a multiple of 6 only appears A2 Any correct step Worthless (0) 5 x − 1 4 x − 9 W1 and stops 2 3 Page 28 2(5 x − 1) + 3(4 x − 9 ) 6 (c) (ii) 5 marks Att2 5(3) − 1 4(3) − 9 + 2 3 15 − 1 12 − 9 = + 2 3 14 3 = + 2 3 = 7 +1 =8 23(3) − 21 6 69 − 21 = and 6 48 = 6 =8 * Accept candidates answer from previous section [May result in inequality]. * Accept usage of a value other than 3 for verification. Blunders (-3) B1 B2 B3 Correct answer without work Substitutes into one expression only Manipulation to force equality Slips (-1) S1 Numerical errors to a max of 3 S2 Conclusion missing if unequal Attempts (2 marks) A1 Writes answer from previous part in this section A2 Substitutes a value into one expression and stops (c) (iii) 10 marks ( x − 2) ( −3x +11) x( −3x +11) −2( −3x +11) − +11x − +6x −22 − +17x −22 * If − +11x − +6x −22 is correct (minimum 7 MARKS) Blunders (-3) B1 Errors in distribution each time B2 Errors in multiplication of powers B3 Errors in grouping of terms (apply once) B4 Mathematical errors eg -2.−3x = -6x B5 Correct answer without work Slips (-1) S1 Numerical errors to a max of 3 Attempts (3 marks) A1 One correct multiplication Page 29 Att 3 QUESTION 6 Part(a) Part (b) Part (c) Part(a) 10(5, 5) marks 30(15, 15) marks 10(5, 5) marks (5, 5)marks P = {(1, 5), (2, 8), (2,9), (3, 10)} Write out the domain and range of P (a)(i) 5marks Att(2, 2) Att(5, 5) Att(2, 2) att(2,2) att2 Domain = {1, 2, 3} * Accept {1, 2, 2, 3} for full marks. Slips (-1) S1 Each incorrect element omitted / included other than the misreading below Misreadings (-1) M1 Correct range {5, 8, 9, 10} given Attempts (2 marks) A1 Any one correct element of the Domain Worthless (0) W1 No element of the domain appears, but note M1. (a)(ii) 5marks Range = {5, 8, 9, 10} Slips (-1) S1 Each incorrect element omitted / included other then the misreading below Misreadings (-1) M1 Correct domain {1, 2, 3} or {1, 2, 2, 3} given Attempts (2 marks) A1 Any one correct element of the Range A2 Range 5 10 Worthless (0) W1 No element of the range appears but note M1 Page 30 att2 Part(b) 30(15, 15)marks att (5, 5) Draw the graph of the function f : x → 3 + 2x − x2 in the domain − 1 ≤ x ≤ 3 , where x ∈ R . Table A 15 marks f (−1) = 3 + 2(−1) -(-1)2 = 0 f (0) = 3 + 2(0) - (0) 2 = 3 f (1) = 3 + 2(1) - (1) 2 = 4 f (2) = 3 + 2(2) - (2) 2 = 3 f (3) = 3 + 2(3) - (3) 2 = 0 Att 5 B x 3 + 2x −x 2 f (x) -1 3 0 3 1 3 2 3 3 3 -2 -1 0 0 +2 -1 +4 -4 +6 -9 0 3 4 3 0 * Error(s) in each row/column calculation attracts a maximum deduction of 3marks Blunders (-3) B1 B2 B3 B4 B5 B6 B7 B8 B9 Correct answer, without work i.e. 5 correct couples only and no graph - taken as + all the way but see M1 “+2 x ” taken as “2” all the way. [In the row headed “+2 x ” by candidate] “3” calculated as “3 x ” all the way. [In the row headed “3” by candidate] Adds in top row when evaluating f (x) in B Omits “3” row Omits “+2 x ” row Omits a value in the domain (each time). Each incorrect image without work i.e. calculation through the function method (A) Slips (-1) S1 Numerical errors to a max of 3 in any row / column Misreadings (-1) M1 Misreads “ − x 2 ” as “ + x 2 ” and places “ + x 2 ” in the table or function M2 Misreads “ + 2 x ” as “ − 2 x ” and places “ − 2 x ” in the table or function M3 Misreads “3” as “-3” and places “-3” in the table or function Attempts (5 marks) A1 Omits “ − x 2 ” row from table or treats “ − x 2 ” as ± x or ± 2 x A2 Any effort at calculating point(s) A3 Only one point calculated and stops Page 31 Graph 15 marks Att 5 (i) 4 3 2 (ii) 1 -1 * * * 1 2 3 accept candidates values from previous work ( 5 co-ordinates needed ) but see S2 Only one correct point graphed correctly ⇒ Att 5 + Att 5 Correct graph but no table ⇒ full marks i.e. (15 + 15) marks. Blunders ( -3) B1 Reversed co-ordinates plotted against non-reversed axes (once only) {See S3 below}. B2 Scale error (once only) B3 Points not joined or joined in incorrect order (once only). Slips (-1) S1 Each point of candidate graphed incorrectly. {Tolerance ± 0.25 } S2 Each point { 5 points needed } from table not graphed [ See * above ] S3 reversed co-ordinates if (i) axes not labelled or (ii) axes are reversed to compensate (see B1 above) Attempts (5 marks) A1 Graduated axes (need not be labelled) A2 Some effort to plot a point { See * above} Page 32 Part (c) (c) 10(5, 5) marks (i) Att(2, 2) Draw the axis of symmetry of the graph you have drawn in part (b) above. Work to be shown on the graph. (ii) Use the graph you have drawn in part (b) to estimate the value of 3 + 2 x − x 2 when x = 2.5 (c) (i) 5 marks Att 2 (i) 4 3 2 1 -1 (ii) 1 2 3 * Accept any vertical line (parallel to candidate’s y-axis) within tolerance of ± 0.25 . Blunders ( -3) B1 Any vertical line (parallel to the candidate’s y-axis) outside of the tolerance. B2 Marks x = 1 on the x-axis and stops. B3 States x = 1 but no line is indicated on the graph Attempts ( 2 marks) A1 Any attempt at axial symmetry of f (x) . A2 y-axis indicated as the axis of symmetry (See B1). (c) (ii) 5 marks Att 2 Work to be shown on the graph and answer to be written here. 1.8 * Correct answer (clearly consistent with student’s graph) inside the tolerance without graphical indication ⇒ 2 marks. Blunders (-3) B1 Correct answer without work B2 Answer on the diagram but outside of tolerance ( ± 0.25 ) B3 Fails to write down the answer, when indicated correctly on graph Slips (-1) S1 Answer not written in box when written on graph Attempts (2 marks) A1 Attempt at algebraic evaluation or calculator. A2 Marks 2.5 in any way on either axis and stops. Worthless (0) W1 Answer outside of tolerance without graphical indication. Page 33 JUNIOR CERTIFICATE EXAMINATION 2009 MARKING SCHEME MATHEMATICS ORDINARY LEVEL PAPER 1 Page 1 GENERAL GUIDELINES FOR EXAMINERS 1. Penalties of three types are applied to candidates’ work as follows: Blunders - mathematical errors/omissions (-3) Slips- numerical errors (-1) Misreadings (provided task is not oversimplified) (-1). Frequently occurring errors to which these penalties must be applied are listed in the scheme. They are labelled: B1, B2, B3,…, S1, S2,…, M1, M2,…etc. These lists are not exhaustive. 2. When awarding attempt marks, e.g. Att(3), note that any correct, relevant step in a part of a question merits at least the attempt mark for that part if deductions result in a mark which is lower than the attempt mark, then the attempt mark must be awarded a mark between zero and the attempt mark is never awarded. 3. Worthless work is awarded zero marks. Some examples of such work are listed in the scheme and they are labelled as W1, W2,…etc. 4. The phrase “hit or miss” means that partial marks are not awarded – the candidate receives all of the relevant marks or none. 5. The phrase “and stops” means that no more work is shown by the candidate. 6. Special notes relating to the marking of a particular part of a question are indicated by an asterisk. These notes immediately follow the box containing the relevant solution. 7. The sample solutions for each question are not intended to be exhaustive lists – there may be other correct solutions. 8. Unless otherwise indicated in the scheme, accept the best of two or more attempts – even when attempts have been cancelled. 9. The same error in the same section of a question is penalised once only. 10. Particular cases, verifications and answers derived from diagrams (unless requested) qualify for attempt marks at most. 11. A serious blunder, omission or misreading results in the attempt mark at most. 12. Do not penalise the use of a comma for a decimal point, e.g. €5.50 may be written as €5,50. Page 2 QUESTION 1 Part (a) Part (b) Part (c) 10 marks 20(5,5,5,5) marks 20(10,5,5) marks Part (a) P = {w, x, y, z} Att 3 Att 2,2,2,2 Att 3,2,2 10 marks Att 3 Q = {v, w, x} Fill the elements of P and Q into the following diagram. P (a) Q 10 marks Att 3 Q P y z w x v * • Not necessary Slips (-1) S1 Each element incorrectly filled into the diagram S2 Each element omitted from the diagram but see W1 S3 Each unlisted element used Misreadings (-1) M1 Interchanging P and Q totally Attempts (3 marks) A1 Totally incorrect filling of the Venn diagram using given elements Worthless W1 No filling in of the Venn diagram or use of unlisted elements only Page 3 (b) (b) 20(5,5,5,5) marks Att 2,2,2,2 U U is the universal set. A = {1, 5, 6, 9, 10} B = {1, 3, 5, 8} C = {4, 5, 8, 10} A 9 6 1 5 10 B 3 ●8 2 4 C 7 (i) List the elements of B C . (ii) List the elements of A' , the complement of the set A. (iii) List the elements of ( B C ) \ A . (iv) Write down #B. (b)(i) 5 marks B C = {1, 3, 4, 5, 8, 10} Blunders (-3) B1 Any incorrect set of the elements of B and C other than the misreading as below Misreadings (-1) M1 B∩C giving {5, 8} Attempts (2 marks) A1 2, 6, 9 or 7 appear in the answer Page 4 Att 2 (b) (ii) 5 marks A' = {2, 3, 4, 7, 8} Att 2 Blunders (-3) B1 Any incorrect set of elements of A' other than the misreadings below. Misreadings (-1) M1 A\B giving {6,9,10}.A\C giving {6,9,1} or A\( B C ) giving{6,9}. Attempts (2 marks) A1 2, 4, 7, 8 or 3 appear in the answer. A2 A or any proper subset of A . (b) (iii) 5 marks (B C) \ A = 8 Att 2 Blunders (-3) B1 Any incorrect set of elements of A and B and C other than the misreading as below. Misreadings (-1) M1 ( B C )/A giving {3, 4, 8,}, A\(B∩C) giving {1,6,9,10} Attempts (2 marks) A1 2 or 7 appear in the answer. (b) (iv) 5 marks #B.= 4 Blunders (-3) B1 Any incorrect cardinal number of B ≤ 10 other than the misreading as below. Misreadings (-1) M1 Set B giving {1, 3, 5, 8}. M2 #B = 6 i.e, # B' Attempts (2 marks) A1 Some understanding of notation e.g. Cardinal numbers or number of elements A2 #B = 17 or 120 Worthless W1 Any number greater than 10, but see A2 Page 5 Att 2 Part(c) 20(10,5,5) marks Att3,2,2 1(c) In a survey, a group of students were asked if they were studying French or German at school. 80 of these students said they were studying French (F). 24 of these students said they were studying German (G). 15 of these students said they were studying both French and German. 11 of these students said they were studying neither of the two languages. (i) Represent this information in the Venn diagram below. (ii) How many students were in the group? (iii) How many students did not study German? (c)(i) (c)(i) 10 marks Att 3 F G 65 15 9 11 * .Failing to subtract 15 from 80 and/or 24 is one blunder only(-3) Blunders (-3) B1 Each incorrect or omitted entry but see S1 and M1 below and * above Slips (-1) S1 Numerical errors, where work is clearly shown to a max of 3 Misreadings (-1) M1 Interchanges French and German Attempts (3 marks) A1 Any one correct relevant entry Page 6 (c)(ii) c(ii) * * 5 marks 65 + 15 + 9 + 11 = 100 Att 2 Any correct answer written here in the space provided takes precedence over an incorrect Venn diagram (Subject to S1) Accept candidate’s work from previous part c(i) Blunders (-3) B1 Any incorrect use of the given numbers or the numbers from an incorrect Venn diagram (Subject to S1) B2 Number of students = 11+15+24+80 = 130 Slips (-1) S1 Numerical errors where work is clearly shown, to a max of 3 S2 Fails to finish Attempts (2 marks) A1 Any one correct relevant sum where work is clearly shown Worthless W1 Incorrect answer with no work shown (c)(iii) 5 marks c(iii) 65 + 11 = 76 or 100-24 * * Att 2 Any correct answer written here in the space provided takes precedence over an incorrect Venn diagram (Subject to M1) Accept candidate’s work from previous part c(i) Blunders (-3) B1 Any incorrect use of the given numbers or the numbers from an incorrect Venn diagram (Subject to S1) Slips (-1) S1 Numerical errors, where work is clearly shown to a max of 3 S2 Fails to finish. Misreadings (-1) M1 German read as French (Ans. = 20). Attempts (2 marks) A1 Mention of 65 or 11 or candidate’s work from c(i) Worthless W1 Incorrect answer with no work shown Page 7 QUESTION 2 Part (a) Part (b) Part (c) 10 marks 20(5,10,5) marks 20(10,5,5) marks Att 3 Att 2,3,2 Att 3,2,2 Part (a) 10 marks (a) 9 metres of cloth cost €13·95. Find the cost of 20 metres of the same cloth. (a) Method (1) Method (2) 9m = 13.95 9:20 9:20 = 13.95:x 13.95 1.55 9 20m=1.55 20=31 13.95 1.55 9 1.55 20=31 9 13.95 = 20 x 9x = 13.95 20=279 279 x= = 31 9 1m = * * * * 10 marks Method (3) Att 3 Method (4) 13.95 20 9 1.55 20 31 Correct answer without work 7 marks 9 Special Case ×13.95 = 6.2775 7 marks 20 13.95 Stops at 1.55 or [=1.55] 4 marks (no use of 20(-3) and B4 or B5 9 Stops at 13.95 ×20[= 279] 4 marks (no use of 9 and possible slips) 31 Incorrect answer without work 0 marks except 279,155 or equivalent 20 Blunders (-3) B1 Divisor ≠ 9 and continues but see 2nd * B2 Incorrect multiplier i.e. ≠ 20 and continues but see 2nd * B3 20 : 9 =13.95 : x and continues B4 Error in decimal point (once only) B5 Fails to finish Slips (-1) S1 Numerical errors where work is clearly shown to a max of 3 Attempts (3 marks) 20 A1 Indicates or 9 : 20 or 13.95 : x ,only, and stops 9 21 A2 279 or 1.55 or , only, appears 20 1 A3 only appears 9 A4 13.95 9 or 13.95 20 and stops or continues A5 13.95 is multiplied or divided by any wrong number correctly Worthless W1 13.95 +9 = 22.95 or similar * Page 8 Att 3 Part (b) (i) (ii) 20(5,10,5) marks Att 2,3,2 a9 a3 6 2 Simplify a a , giving your answer in the form a n , where n N. By rounding each of these numbers to the nearest whole number, estimate the value of 18 207 3 7 2 08 . (iii) Using a calculator, or otherwise, find the exact value of (b)(i) 5 marks a a a = a4 8 6 2 a a a 9 (i) or * * * * * 18 207 . 3 7 2 08 3 12 Att 2 a a = a3 a = a 4 6 2 a a 9 or 3 a9 a3 a a a a a a a a a a a a = = a4 6 2 a a a a a a a a a a a12 and stops 2 marks a8 a 12 and stops 2 marks Correct answer without work 2 marks a 3 ×a and stops 2marks a × a ×a × a as answer 2 marks Blunders (-3) B1 Correct answer, without work B2 Each error in calculation involving indices B3 Each incorrect number of a’s in the extended form B4 Each incorrect elimination of a’s in the extended form Slips (-1) 1 a 12 S1 = 4 or 4 as final answer 8 a a Attempts (2 marks) A1 Some correct manipulation of indices Worthless W1 Incorrect answer with no work shown Page 9 (b)(ii) 10 marks 18 18 4 + Att 3 2 = 6 = 3 18 and stops 4 marks. 42 * No penalty if the intermediate step between approximations and correct final answer is not 18 shown i.e. not shown 6 18.207 63 * Special Case: = 3.15 or presented in this part Attempt 3 marks. 3.7 2.08 20 18 and stops 7 marks. * 6 Blunders (-3) B1 Error(s) in rounding off to the nearest whole number (once only) B2 Decimal error in calculation of final value B3 An arithmetic operation other than indicated B4 Error(s) in the manipulation of the denominator B5 Incorrect cancellation Slips (-1) S1 Numerical errors to a max of 3 Attempts (3 marks) A1 Only one or two approximations made to the given numbers and stops. A2 Ans. 3 with no preceding rounding off Worthless (0) W1 Incorrect answer without work * (b)(iii) 5 marks Att 2 18.207 63 3.15 or 5.78 20 * Any of the following; 7.00081081 13.6741762 2.365774428 11.23888889 merit 2 marks (with or without work) 10.23528649 or 12.45336538 Blunders (-3) B1 Decimal error B2 Fails to finish Slips (-1) S1 Numerical errors to a max of 3 S2 Any rounding off. Attempts (2 marks) A1 Any correct relevant calculation and stops. 18.207 e.g. . 4.9208 or similar 3.7 Worthless (0) W1 Incorrect answer without work but see * Page 10 Part (c) 2(c) 20(10,5,5) marks (i) (ii) (iii) * Note: Att 3,2,2 1 13 and as decimals. 8 80 Hence or otherwise, put the following numbers in order, starting with the smallest and finishing with the largest: 1 13 , , 0·1525. 8 80 Using a calculator, or otherwise, write 1 2 Using a calculator, or otherwise, find the exact value of (3 61) . Using a calculator, or otherwise, evaluate 1 94 09 (2 75) 2 − . 0 3125 Give your answer correct to two decimal places. 1 13 0 125 . or 0.1625 . merits 4 marks. 8 80 (c)(i) 10marks 1 = 0.125 8 1 8 * Accept: * Note: Att 3 13 = 0.1625 80 0.1525 0.125, 0.1525, 0.1625, merits 10 marks. 1 13 0 125 or 0 1625 merits 4 marks 8 80 Blunders (-3) B1 Fails to write a fraction as a decimal (each time) B2 Writes fraction as incorrect decimal (each time) B3 Decimal error (once only if consistent) B4 Inverts fraction and continues. (each time) B5 Incorrect order or fails to order. Attempts (3 marks) 1525 A1 and stops 0.1525 10000 A2 Attempt at ordering Worthless(0) W1 Nothing correct Page 11 13 80 (c)(ii) 5 marks 19 1.9 or 10 Att 2 Blunders (-3) B1 Squares B2 Decimal error Attempts (2 marks) A1 mentions square root or power Worthless(0) W1 Dividing by 2 or multiplying by 2 (c)(iii) * * * * 5 marks 9.7 × 7.5625 –3.2 = 70.15625 = 70.16 answer 70.15625 2 marks answer 70.15625 = 70.16 5 marks 2245 [ ] as final answer 0 marks but = 70.15625 4 marks 32 Ans 70.15 (no work shown) 2 marks Att 2 Blunders (-3) B1 B2 B3 B4 Correct answer, without work Decimal error Inverts fraction Incorrect operator Slips (-1) S1 Numerical errors to a max of 3 S2 Fails to give answer to 2 dec. places S3 Each premature rounding off, that effects final answer,( to a maximum of 3marks) Attempts (2 marks) A1 Any relevant step. e.g. Partial long division or similar Page 12 QUESTION 3 Part (a) Part (b) Part (c) 10 marks 20(10,10) marks 20(10,10) marks Att 3 Att 3,3 Att 3,3 Part (a) 10 marks (a) Aideen owns 6000 shares in a certain company. She sells two-thirds of her shares. How many shares does she now own in the company? Att 3 (a) Att3 10 marks 6000 ÷ 3 = 2000 or Number of shares sold: Shares now owned: 6000 x ⅔ = 4000 6000 - 4000 = 2000 Blunders (-3) B1 Correct answer without work B2 6000 ⅔ B3 Calculates the number of shares sold and stops B4 Operation other than subtraction in final step Slips (-1) S1 Numerical errors (to max -3) S2 Early rounding off Attempts (3 marks) A1 Any attempt at getting ⅔ of 6000 1 6000 A2 Writes down or 3000 3 2 Page 13 Part (b) (i) (ii) 20(10,10) marks Att 3,3 Brian’s gross annual pay is €26 000. His annual tax credit is €2800. He pays income tax at the rate of 20%. What is his annual take-home pay? A dealer buys a car for €17 500. He sells the car for €23 800. Calculate his profit as a percentage of the cost price. (b)(i) 10 marks Att 3 (i) Brian’s gross annual pay is €26 000. His annual tax credit is €2800. He pays income tax at the rate of 20%. What is his annual take-home pay? (b)(i) 10 marks €26 000 Gross Pay * Att 3 Tax @ 20% 5200 Tax Credit €2800 Tax Due 2400 Take-home Pay 23600 26000 20 5200 5200 – 2800 = 2400 100 Finds Tax Due 2400 and stops 7 marks 26000 – 2400 = 23600 (at least 2 out 3 boxes filled in) Blunders (-3) B1 Correct answer, without work. B2 Mishandles 20% of 26,000. {Must use 26,000} B3 Decimal error B4 Misuse of Tax Credit B5 Incorrect use of Tax Amount e.g. 26000 + 5200 B6 Fails to finish. {B4 may apply} Slips (-1) S1 Numerical errors to a max of 3 Attempts (3 marks) A1 Some use of 100 in attempt to find percentage e.g. 20% = 20/100 and stops. Worthless (0) W1 Incorrect answer without work Page 14 (b) (ii) 10 marks Att 3 (b) (ii) A dealer buys a car for €17 500. He sells the car for €23 800. Calculate his profit as a percentage of the cost price. (b)(ii) 10 marks 23800 – 17500 = 6300 Att 3 6300 100 36% 17500 23800 100 136 136 – 100 = 36% 17500 * Answer 6300 4 marks 6300 * 17500 1102500 7 marks 100 Blunders (-3) B1 Correct answer without work B2 Adds €17 500 to €23 800. B3 Calculates profit as percentage of selling price. B4 Divisor not equal to 17500 or Method 2: B5 Mishandles the calculation of profit as a percentage e.g. B6 B7 B8 Incorrect cancellation(s) Fails to multiply by 100 Fails to finish Slips (-1) S1 Numerical errors to a max of 3 Attempts (3 marks) A1 Some indication of subtraction A2 Some use of 100 Page 15 6300 17500 100 Part (c) 20(10,10) marks 3(c) (i) €20 000 is invested at 5 2% per annum. What is the amount of the investment at the end of one year? Att 3,3 (ii) €5000 is withdrawn from this amount at the beginning of the second year. The interest rate for the second year is 6 25% per annum. What is the amount of the investment at the end of that year? (c)(i) 10 marks 20000 5.2 1040 20000 + 1040 = €21040 100 or or 20000 1%= 100 20000 5.2% = 5.2 100 Interest = 1040 Amount = 20000 1040 Amount = 21040 * * * * Att3 or PR I 100 20000 I = 5.2 100 Interest = 1040 Amount = 20000 1040 Amount = €21040 20000 × 1.025 = 21040 or Amount = 20000 1 052 Amount = €21040 € 1040 (without work) and stops 4 marks. Writes down 20000 +5.2% = 21040 10 marks Writes down 20000 ×5.2% = 1040 and stops 7 marks. Writes down 20000 ×5.2% and stops, or 20000 +5.2% and stops 4 marks. Blunders (-3) B1 B2 B3 B4 B5 B6 Correct answer without work 20000 Mishandles 5.2 %. e.g. 100 Note: {20000 must be used}. 5.2 Decimal error (once only) Stops at interest i.e. fails to calculate amount. Subtracts to calculate amount. 1 052 treated as 1 52 . Slips (-1) S1 Numerical errors to a max of 3 Misreadings (-1) M1 Reads as €2000 Page 16 Attempts (3 marks) A1 Correct formula with or without substitution and stops A2 Some use of 100 in attempt to find percentage e.g. 5.2 % 5.2 or 1 052 and stops. 100 Worthless (0) W1 Incorrect answer without work W2 20000 + 5.2 = 20005.2 and stops or continues. (c)(ii) * * * * * * 10 marks Att3 16040 6.25 21040 – 5000 = 16040 1002.5 100 16040 + 1002.5 = €17042.5 [ or 16040 × 1.0625 = 17042.5 ] Accept candidates answer from (i) € 16040 (without work) and stops 4 marks. 10 marks Writes down 16040 + 6.25% = 17042.5 Writes down 16040 ×6.25% = 1002.5 and stops 7 marks. Writes down 16040 ×6.25% and stops, or 16040 + 6.25% and stops 4 marks. Uses 5000 (-3)(-3). Uses 20000 (-3) Blunders (-3) B1 Correct answer without work B2 Fails to subtract 5000 B3 Mishandles 6.25% B4 Decimal error (once only). B5 Stops at interest i.e. fails to calculate amount. B6 Subtracts to calculate amount. B7 Incorrect Principal Slips (-1) S1 Numerical errors to a max of 3 Misreadings (-1) M1 Reads as €500 or similar. Attempts (3 marks) A1 Correct formula with or without substitution and stops A2 Some use of 100 in attempt to find percentage and stops. A3 21040-5000 = 16040 and stops Worthless (0) W1 Incorrect answer without work W2 21040 + 6.25 and stops or continues Page 17 QUESTION 4 Part (a) Part (b) Part (c) 10 marks 20(10,10) marks 20(5,5,10) marks Part (a) (a) If a = 5, find the value of (a)(i) (i) * 20 + 1 => 4 marks 10 (5,5)marks Att 2,2 Att 3,3 Att 2,2,3 Att 2,2 (i) 4a + 1 (ii) a2 – 3a + 6 5 marks 4(5) + 1 = 21 Blunders (-3) B1 Correct answer, without work B2 Leaves 4(5), in the answer B3 Incorrect substitution and continues B4 Breaks order i.e. 4(5 + 1) = 4.6 = 24 B5 Treats 4(5) as 9 or 45 Slips (-1) S1 Numerical errors to a max of 3 S2 Treats as 4a - 1 Attempts (2 marks) A1 Any number substituted for a and stops e.g. 4(8). A2 Writes 5 in this part A3 Any correct step. Worthless (0) W1 Incorrect answer with no work. Page 18 Att2 (a)(ii) (5)2 – 3(5) + 6 = 16 (ii) * 31 - 15 or 10 + 6 => 4 marks 5 marks or 25-15 + 6 = 10 + 6 = 16 Blunders (-3) B1 Correct answer without work B2 Leaves 52 or -3(5) in the answer B3 Incorrect substitution and continues. B4 Breaks order e.g. -3(5+6). B5 Treats -3(5) as 2 or -35. B6 Fails to finish but see * above Slips (-1) S1 Numerical errors to a max of 3 S2 Treats as a2 – 3a – 6 Attempts (2 marks) A1 Any substitution for either a2 or -3a and stops e.g. (8) etc. A2 writes 5 in this part. A2 Any correct step. Worthless (0 marks) W1 Incorrect answer, with no work. Page 19 Att2 Part (b) 4(b) (i) Solve the equation 20(10,10) marks 5 x 10 3( x 2) . Att 3,3 Multiply ( x 3) by (2 x 1) . Write your answer in its simplest form. (ii) (b)(i) 10 marks 5x – 10 = 3x + 6 => 5x – 3x = 6 + 10 => 2x = 16 => x = 8 (i) Blunders (-3) B1 Correct answer without work (x = 8 stated or substituted). B2 Error in distributive law and continues, e.g. 5x – 10 = 3x + 2. B3 Errors in transposition (each time) B4 Stops at 2x = 16 or similar. Att 3 Slips (-1) S1 Numerical errors to a max of 3 S2 Leaves as 16 or similar. 2 Attempts (3 marks) A1 Any substitution for values of x other than x = 8. A2 Any correct step. A3 Combines “x’s” to numbers and continues with any correct step e.g. 5x – 10 = -5x. Worthless (0 marks) W1 Combines “x’s” to numbers and stops. W2 Incorrect answer, with no work Page 20 (b)(ii) (ii) 2x(x – 3) + 1(x – 3) => 2x2 – 6x + x – 3 => 2x2 – 5x – 3 * 10 marks or Att3 x(2x + 1) – 3(2x + 1) => 2x2 + x – 6x – 3 => 2x2 – 5x – 3 2x2 + x – 6x –3 => 7 marks Blunders (-3) B1 Correct answer without work B2 Error(s) in distribution.(each time) B3 Fails to group or groups incorrectly Slip (-1) S1 Numerical errors to a max of 3. Attempts (3 marks) A1 Any correct multiplication e.g. 2x2 etc. A2 Any correct grouping of terms. A3 Any correct step. A4 Substitutes a value of “x” and continues correctly. A5 Treats as (x – 3)±(2x + 1) to give 3x – 2 or –x – 4 A6 Combines “x’s” to numbers and continues with correct step e.g. x – 3= – 3x or 2x + 1 = 3.x Worthless (0 marks) W1 Combines “x’s” to numbers and stops. W2 No distribution but A2 or A5 may apply to subsequent work e.g. gathering of terms. Page 21 Part (c) 20(5,5,10) marks Att 2,2,3 The cost of a cinema ticket is € t for an adult and €5 for a child. The cost of tickets for 2 adults and 3 children is €33. (i) Write down an equation in t to represent this information. (ii) Solve the equation you formed in part (i) above, for t. (iii) Solve for x and for y: 5x – 4y = 16 2x + 3y = 11 2t + 3(5) = 33 or (c)(i) 5 marks Att2 2t + 15 = 33 Blunders (-3) B1 Each incorrect term in equation Misreading (-1) M1 Substitutes x (or similar) for t Attempt (2 marks) A1 Any attempt at forming an equation but numbers written on their own (except 15 or 33) are worthless (c)(ii) 2t + 15 = 33 * 5marks => 2t = 18 => t =9 Accept candidates’ equation from previous work. Blunders (-3) B1 Correct answer without work (t = 9 stated or substituted). B2 Errors in transposition B3 Stops at 2t = 18 or similar Slip (-1) S1 Numerical errors to a max of 3 S2 Leaves as 18 or similar. 2 Attempts (2 marks) A1 Answer from part c(i) written down and stops A2 Any correct step e.g. 3.5 = 15 Worthless (0 marks) W1 Incorrect answer, with no work Page 22 Att 2 (c)(iii) 10 marks Att 3 I 5x – 4y = 16 2x + 3y = 11 15x – 12y = 48 8x + 12y = 44 23x = 92 II 5x – 4y = 16 2x + 3y = 11 4y = 5x – 16 y = 5 x 16 10x – 8y = 32 –10x – 15y = –55 –23y = –23 x = 92 = 4 23 => y = 1 y = 23 = 1 23 4 x 5 2x + 3( 16 ) = 11 4 8x + 15x – 48 = 44 23x = 92 x=4 => y = 1 => x = 4 Blunders (-3) * Apply only one blunder deduction (B2 or B3) to any error(s) in establishing the first equation; in terms of x only or the first equation in terms of y only. * Finding the second variable is subject to a maximum deduction of (3). Blunders (-3) B1 Correct answers without work(stated or substituted) B2 Error or errors in establishing the first equation in terms of x only (23x = 92) or the first equation in terms of y only (–23y = –23) through elimination by cancellation (but see S1) B3 Errors in transposition when finding the first variable. B4 Errors in transposition when finding the second variable B5 Incorrect substitution when finding second variable B6 Finds one variable only Slips (-1) S1 Numerical errors to a max of 3 Attempt (3 marks) A1 Attempt at transposition and stops A2 Multiplies either equation by some number and stops A3 Incorrect value of x or y substituted correctly to find his correct 2nd variable Worthless (0 marks) W1 Incorrect values for x or y substituted into the equations Page 23 QUESTION 5 Part (a) Part (b) Part (c) 10 marks 15(5,5,5) marks 25(5,10,10) marks Att 3 Att 2,2,2 Att 2,3,3 Part (a) 10 marks (a) Write in its simplest form 3(x + 2) + 4(3x + 1). Att 3 (a) Att 3 10marks * * 3x + 6 + 12x + 4 = 15x + 10 Stops after correct removal of brackets 7marks Ignore excess work 53x 2 Blunders (-3) B1 B2 B3 Correct answer without work Error(s) in distribution (each time) Combining unlike terms Attempts (3 marks) A1 Any correct multiplication B4 Fails to group like terms Slips (-1) S1 Numerical errors to a max of 3 Misreadings (-1) M1 3 x 2 43 x 1 and continues Worthless (0) W1 combining unlike terms, before attempting multiplication and stops Page 24 Part (b) 5(b) 15(5,5,5) marks Att 2,2,2 Factorise (i) 5cd 7 d (ii) ax 3ay 4 x 12 y (iii) x 2 49 (b)(i) 5 marks Att 2 d 5c 7 Blunders (-3) B1 Removes factor incorrectly. Attempts (2 marks) A1 Indication of common factor e.g. underline ds and stops. (b) (ii) 5marks ax 3ay 4 x 12 y a x 3 y 4 x 3 y ax 4 x 3ay 12 y xa 4 3 y a 4 or a 4x 3 y Att 2 x 3 y a 4 * Accept also (with or without brackets) for 5 marks any of the following a 4 and x 3 y [The word and is written down.] a 4 or x 3 y [The word or is written down.] a 4 , x 3 y [A comma is used] Blunders (-3) B1 B2 B3 B4 B5 Correct answer without work Stops after first line of correct factorisation e.g. a x 3 y 4x 3 y or equivalent. Error(s) in factorising any pair of terms (each time) (B2 will apply) Incorrect common factor and continues. e.g. xa 4 y 3a 12 Correct first line of factorisation but ends as x 3 y 4 a . Slips (-1) S1 x 3 y a 4 Attempts (2 marks) A1 Pairing off, or indication of common factors and stops. A2 Correctly factorises any pair and stops. Page 25 (b) (iii) 5 marks Att 2 x 49 2 * * * x2 72 x 7 x 7 Accept also (with or without brackets) for 5 marks any of the following x 7 and x 7 [The word and is written down.] x 7 or x 7 [The word or is written down.] x 7 , x 7 [A comma is used] Quadratic equation formula method is subject to slips and blunders. x 49 x 49 merits 5 marks Blunders (-3) B1 Incorrect two term linear factors of x 2 49 formed from correct (but inapplicable) factors of x 2 and 49 .e.g. x 49 x 1 B2 Incorrect factors of 49 B3 Incorrect factors of x 2 B4 7 x 7 x . B5 x 49 x 49 . B6 Answer left as roots. ( x 7 ) Slips (-1) S1 x 7 ± x 7 Attempts (2 marks) A1 Correct factors of x 2 only A2 Correct factors of 49 only A3 x or 7 appears. A4 x 2 49 x x 7 7 A5 Mention of the difference of two squares .e.g. x 2 49 2 A6 Correct quadratic equation formula quoted and stops. 49 A7 Worthless (0 marks) W1 Combines xs to “numbers” and continues or stops. Page 26 Part (c) (i) (ii) 25(5,10,10) marks Att 2,3,3 5x 1 x6 as a single fraction. 3 5 Give your answer in its simplest form. Express Verify your answer to part (i) by substituting x = 4 into 5x 1 x 6 3 5 and into your answer to part (i). (iii) Solve the equation x 2 4 x 21 0. (c)(i) (i) 5 marks 5(5 x 1) 3( x 6) 25 x 5 3x 18 22 x 13 = = 15 15 15 5x 1 4x 7 x 6 3 5 2 Blunders (-3) * Zero marks B1 B2 B3 B4 Correct answer, without work Error(s) in distribution e.g. 55 x 1 5 x 1 . Mathematical error e.g. 5-18=13 , -3(6) =18 Incorrect common denominator and continues B5 Incorrect numerator, from candidate's denominator e.g. B6 B7 No simplification of numerator Omitting denominator Slips (-1) S1 Drops denominator S2 Numerical errors to a max of 3 S3 Att2 Answer not in simplest form. e.g. 44 x 2 6 . 30 Attempts (2 marks) A1 15 only or a multiple of 15 only appears. A2 Any correct step. Worthless (0) 5 x 1 x 6 W1 and stops. 3 5 Page 27 35 x 1 5x 6 . 15 Part(c) (ii) * * 10 marks 5(4) 1 4 6 3 5 20 1 10 5 3 21 10 3 5 72 5 and Att 3 22 x 14 15 22(4) 13 15 88 13 15 75 15 5 Accept candidates answer from previous section [May result in inequality]. Accept usage of a value other than 4 for verification. Blunders (-3) B1 B2 B3 B4 Correct answer, without work Substitutes into one expression only (B4 will also apply) Manipulation to force equality Conclusion missing Slips (-1) S1 Numerical errors to a max of 3 Attempts (3 marks) A1 Writes answer from previous part in this section A2 Substitutes a value into one expression and stops Page 28 (c) (iii) 10 marks Att 3 x 2 4 x 21 0 x x 2 7 x 3 x 21 0 x x 7 3 x 7 0 +3 x 7 x 3x 7 0 x 3 and x 7 x 3 x 7 0 x 7 and x 3 4 42 41 21 21 4 16 84 2 14 7 and 2 x 7 and 4 10 2 6 3 2 x 3 Factor Method Blunders (-3) B1 B2 B3 B4 B5 B6 B7 Correct answers without work Incorrect two term linear factors of x 2 4 x 21 formed from correct (but inapplicable) factors of x 2 and/or ±21. e.g. (x+21)(x-1) No roots given.(each time) Incorrect factors of x 2 and/or ±21. Correct cross method but factors not shown and stops [Note: B3 applies also]. x(x-7) +3(x-7) or similar and stops [Note: B3 applies also]. Error in transposition (each time) Slips (-1) S1 Numerical errors, to a max of 3 Attempts (3 marks) A1 Some effort at factorisation A2 One correct answer without work Worthless (0 marks) W1 x 2 4 x 21 , or similar, and stops. W2 Trial and error W3 Oversimplification, resulting in a linear equation Formula Method Blunders (-3) B1 B2 B3 B4 Correct answers without work. Error in a,b,c substitution (apply once only) Sign error in substituted formula (apply once only) Error in square root or square root ignored. Page 29 B5 B6 4 10 2 Incorrect quadratic formula and continues. Stops at Slips (-1) S1 Numerical errors to a max of 3 p S2 Roots left in the form q Attempts (3 marks) A1 Correct formulas and stops A2 One correct substitution and stops Page 30 QUESTION 6 Part (a) Part (b) Part (c) 10(5,5) marks 25(10,15) marks 15(10,5) marks Att 2,2 Att 3,5 Att 3,2 Part (a) (a) 10 (5,5)marks Att 2,2 f (x) = 4x – 5. Find: (i) f(3) (ii) f(-2) (a)(i) 5 marks f (3) 4(3) 5 12 5 7 * Answer 12-5 4 marks Blunders (-3) B1 Correct answer no work. B2 Leaves 4(3) in the answer B3 Mathematical error e.g. treats 4(3) as 43. B4 Breaks order i.e. [ 4 3 5 4(2) 8 ]. Slips (-1) S1 Numerical errors to a max of 3 S2 Leaves x in the answer e.g. 7x Misreadings (-1) M1 Correct substitution of any number other than 3 and continues. Attempts (2 marks) A1 Substitutes for x and stops e.g. 4(3) A2 Treats as an equation and continues or stops 4 x 5 3 A3 Combines "x"s to “numbers” and continues. e.g. 4 x 5 x (3) Worthless (0) W1 Combines "x"s to “numbers” and stops. W2 Ignores x giving 4 5 1 3 f ( x ) 12 x 15 W3 W4 Replaces coefficient i.e. 4 x 3x W5 Incorrect answer, without work Page 31 Att 2 (a) (ii) 5 marks f (2) 4(2) 5 8 5 13 * Answer -8-5 4 marks (stops or continues) * -8x -5x = 13x 4marks but -8x -5x = 13 5marks (rectified error) Blunders (-3) B1 Correct answer no work B2 Leaves 4(-2) in the answer B3 Mathematical error e.g. treats 4(-2) as 42 . B4 Breaks order i.e. [ 4 2 5 4(7) 28 ]. Slips (-1) S1 Numerical errors to a max of 3 S2 Leaves x in the answer e.g. -13x A3 Combines "x"s to “numbers” and continues. e.g. 4 x 5 x (2) 2 A4 Substitutes positive value for x and continues correctly Misreadings (-1) M1 Correct substitution of any negative number other than -2 and continues Attempts (2 marks) A1 Substitutes for x and stops e.g. 4(-2) A2 Treats as an equation and continues or stops 4 x 5 2 Worthless (0) W1 Combines "x"s to “numbers” and stops W2 Ignores x giving 4 5 1 W3 2 f ( x ) 8 x 10 W4 Replaces coefficient i.e. 4 x 2 x W5 Incorrect answer, without work Page 32 Att 2 Part (b) 25(10,15) marks Draw the graph of the function f : x x 2 2x 1 (b) in the domain 1 x 3, where x R. Table * Att 3,5 2 10marks 2 x f(-1) = (-1) -2(-1) -1 = f(0) = (0)2 -2(0) -1 = -1 f(1) = (1)2 -2(1) -1 = -2 f(2) = (2)2 -2(2) -1 = -1 f(3) = (3)2 -2(3) -1 = 2 Att 3 -1 0 1 2 3 x2 1 0 1 4 9 -2 x 2 0 -2 -4 -6 -1 -1 -1 -1 -1 -1 f x 2 -1 -2 -1 2 Error(s) in each row /column calculation attracts a maximum deduction of 3 marks Blunders (-3) B1 Correct answer, without work i.e. 5 correct couples only and no graph B2 “ 2 x ” taken as “2” all the way. [In row headed ” 2 x ” by candidate] B3 “-1” calculated as “–x” all the way. [In row headed “-1” by candidate] B4 Adds in top row when evaluating f (x) . B5 Omits “-1” row B6 Omits “-2 x ” row B7 Omits a value in the domain (each time). B8 Each incorrect image without work i.e. calculation through the function method Slips (-1) S1 Numerical errors to a max of 3 in any row / column Misreadings (-1) M1 Misreads “ x 2 ”as “ x 2 ”and places ''- x 2 '' in the table or function. M2 Misreads “-2x”as “2x” and places “2x” in the table or function. M3 Misreads “-1”as “1” and places “1” in the table or function Attempts (3 marks) A1 Omits “ x 2 ”row from table or treats “ x 2 ” as xor 2 x . A2 Any effort at calculating point(s). A3 Only one point calculated and stops. Page 33 Graph 15 Marks Att 5 y-axis 3 2 1 x-axis -1 1 2 3 -1 -2 * * * * Accept candidate's values from previous work.( 5 co-ordinates needed ) but see S2 Only one correct point graphed correctly Att 3 + Att 5 Correct graph but no table full marks i.e. (10+15) marks. Accept reversed co-ordinates if (i) if axes not labelled or (ii) if axes are reversed to compensate (see B1 below) Blunders (-3) B1 Reversed co-ordinates plotted against non-reversed axes (once only) {See 4th * above}. B2 Scale error (once only). B3 Points not joined or joined in incorrect order (once only). Slips (-1) S1 Each point of candidate graphed incorrectly. {Tolerance 0.25 } S2 Each point ( 5 points needed ) from table not graphed [See 2nd * above]. Attempts (5 marks) A1 Graduated axes (need not be labelled) A2 Some effort to plot a point {See 2nd * above} Page 34 Part (c) 15(10,5) marks Use the graph drawn in 6(b) to estimate: (i) Att 3,2 the values of x for which x 2 2 x 1 0 (ii) the value of f(x) when x 1 5 . (c) (i) 10 marks x 2.4 and x 0.4 work to be shown on graph for correct answer * * Accept candidate's values from previous work. 2 indications on graph and 2 values written down (blunder each time) Blunders(-3) B1 Answers beyond tolerance. {Tolerance 0.25 } Misreading (-1) M1 Answers not presented in designated box (but elsewhere) . Attempts (3marks) A1 One point of intersection indicated only or one value of x written down A2 Algebraic evaluation ( x = 1 √2) Worthless (0) W1 Answers outside of tolerance without graphical indication W2 f(0) gives -1 as answer. Page 35 Att 3 (c) (ii) * 5 marks f(x) = -1.75 work to be shown on graph for correct answer Accept candidate's values from previous work. Blunders (-3) B1 Answer beyond tolerance. {Tolerance 0.25 }. B2 Correct answers no work B3 Sign error Misreading (-1) M1 Answers not presented in designated box (but elsewhere) Attempts (2 marks) A1 Point indicated only. A2 Algebraic evaluation or correct calculator calculation. A3 Testing x value for y = 1.5 Worthless(0) W1 Answers outside of tolerance without graphical indication. Page 36 Att 2 JUNIOR CERTIFICATE 2008 MARKING SCHEME MATHEMATICS ORDINARY LEVEL PAPER 1 GENERAL GUIDELINES FOR EXAMINERS 1. Penalties of three types are applied to candidates’ work as follows: • Blunders - mathematical errors/omissions (-3) • Slips- numerical errors (-1) • Misreadings (provided task is not oversimplified) (-1). Frequently occurring errors to which these penalties must be applied are listed in the scheme. They are labelled: B1, B2, B3,…, S1, S2,…, M1, M2,…etc. These lists are not exhaustive. 2. When awarding attempt marks, e.g. Att(3), note that • any correct, relevant step in a part of a question merits at least the attempt mark for that part • if deductions result in a mark which is lower than the attempt mark, then the attempt mark must be awarded • a mark between zero and the attempt mark is never awarded. 3. Worthless work is awarded zero marks. Some examples of such work are listed in the scheme and they are labelled as W1, W2,…etc. 4. The phrase “hit or miss” means that partial marks are not awarded – the candidate receives all of the relevant marks or none. 5. The phrase “and stops” means that no more work is shown by the candidate. 6. Special notes relating to the marking of a particular part of a question are indicated by an asterisk. These notes immediately follow the box containing the relevant solution. 7. The sample solutions for each question are not intended to be exhaustive lists – there may be other correct solutions. 8. Unless otherwise indicated in the scheme, accept the best of two or more attempts – even when attempts have been cancelled. 9. The same error in the same section of a question is penalised once only. 10. Particular cases, verifications and answers derived from diagrams (unless requested) qualify for attempt marks at most. 11. A serious blunder, omission or misreading results in the attempt mark at most. 12. Do not penalise the use of a comma for a decimal point, e.g. €5·50 may be written as €5,50. Page 1 QUESTION 1 Part (a) Part (b) Part (c) 10(5, 5) marks 20 (5, 5, 5, 5) marks 20 (5, 5, 5, 5) marks Att 4(2, 2) Att 8 (2, 2, 2, 2) Att 8 (2, 2, 2, 2) Part (a) (i) 5 marks S = {a, b, c} 1(a) (i) Write down a subset of S that has one element Att 2 Part (a) (i) Att 2 * * 5 marks {a} or {b} or {c}. No penalty for the omission of brackets. No penalty for use of Venn Diagram to show subsets. Blunders (-3) B1 Any incorrect set of elements of S other than the misreading below. Misreadings (-1) M1 Subset of S with two elements. e.g. S = {a, b}. Attempts (2 marks) A1 Draws a single bracket & stops. A2 { } Null set. Part (a) (ii) 1(a) (ii) 5 marks S = {a, b, c} Write down a subset of S that has two elements Part (a) (ii) * * Att 2 5 marks {a,b} or {a,c} or {b,c} No penalty for omission of brackets. No penalty for use of Venn Diagram to show subsets. Blunders (-3) B1 Any incorrect set of elements of S other than the misreading below. Misreadings (-1) M1 Subset of S with one element. e.g. S = {a}. Attempts (2) A1 Draws a single bracket & stops. A2 { } Null set. Page 2 Att 2 Part (b) 1(b) U is the universal set. 20 (5, 5, 5, 5) Att 8 (2,2,2,2) P = {2, 3, 6, 7, 8} P Q = {1, 6, 8, 10} 3 7 R = {2, 4, 6} 1 8 10 6 2 Q 9 4 R Part (b) (i) 1 (b) (i) 5 marks 5 Att 2 List the elements of: P ∩ Q Part (b) (i) 5 marks P ∩ Q = {6, 8} Att 2 Blunders (-3) B1 Any incorrect set of elements of P and Q other than the misreading below. Misreadings (-1) M1 P ∪ Q = {1,2 , 3, 6, 7, 8,10}. Attempts (2 marks) A1 4 or 5 or 9 appear in the answer. Part (b) (ii) 1 (b) (ii) 5 marks Att 2 List the elements of: Q \ R Part (b) (ii) 5 marks Q \ R = {1, 8,10} Blunders (-3) B1 Any incorrect set of elements of Q and R other than the misreading below. Misreadings (-1) M1 R \ Q = { 2, 4 }. Attempts (2 marks) A1 3 or 5 or 7 or 9 appear in the answer. Page 3 Att 2 Part (b) (iii) 1 (b) (iii) 5 marks List the elements of: (Q ∪ R ) Part (b) (iii) Att 2 / 5 marks (Q ∪ R ) = {3, 5, 7, 9} Att 2 / Blunders (-3) B1 Any incorrect set of elements of Q and R other than the misreadings below. B2 (Q ∪ R ) = {1, 2, 4, 6, 8,10} Misreadings (-1) / M1 (Q ∩ R ) = {1,2 , 3, 4, 5, 7,8,9,10} M2 Q / ∪ R / = {1, 2, 3, 4, 5, 7, 8, 9,10} Attempts (2 marks) A1 Any incorrect listing of element(s) other than the misreadings above. Part (b) (iv) 1 (b) (iv) 5 marks Att 2 List the elements of: (P ∩ R ) \ Q Part (b) (iv) 5 marks (P ∩ R ) \ Q = {2} Att 2 Blunders (-3) B1 Any incorrect set of elements of P and Q and R other than the misreadings below. B2 P ∩ R = {2, 6 } Misreadings (-1) M1 Q \ (P ∩ R ) = {1, 8,10 }. M2 (P ∪ R ) \ Q = {2,3,4,7} Attempts (2 marks) A1 5 or 9 appear in the answer. Page 4 Part(c) 20(5, 5, 5, 5) Att 8 (2, 2, 2, 2) M is the set of natural numbers from 1 to 36, inclusive Part (c) (i) 5 marks 1(c) (i) List the elements of M that are multiples of 6. Att 2 Part (c) (i) Att 2 5 marks 6, 12, 18, 24, 30, 36. Slips (-1) S1 Each missing or incorrect element subject to a max of 3. Attempts (2 marks) A1 Any one correct element identified. A2 Any correct factor(s) of 6. Worthless (0) W1 Elements listed are not multiples or factors of 6. Part (c) (ii) 1(c) (ii) Part (c) (ii) 5 marks List the elements of M that are multiples of 9. 5 marks 9, 18, 27, 36. Slips (-1) S1 Each missing or incorrect element subject to a max of 3. Attempts (2 marks) A1 Any one correct element identified. A2 Any correct factor(s) of 9. Worthless (0) W1 Elements listed are not multiples or factors of 9. Page 5 Att 2 Att 2 Part (c) (iii) 5 marks Att 2 1(c) (iii) Write down the lowest common multiple of 6 and 9. * Accept candidate's L.C.M. from incorrect answers in part (i) and part (ii) for full marks. * Accept indication of candidate's L.C.M. Part (c) (iii) 5 marks L.C.M. = 18 Att 2 Blunders (-3) B1 An incorrect common multiple that is not the lowest.e.g. {36}. Slips (-1) S1 Answer written as 2 × 3 × 3 and stops. Misreadings (-1) M1 Writes down H.C.F. = 3. Attempts (2 marks) A1 Any multiple of either 6, or 9 written in this part. Worthless (0) W1 Elements listed are not multiples of 6 or 9. Part (c) (iv) 1(c) (iv) 5 marks Express 30 as the product of three prime numbers, Part (c) (iv) * 5 marks 30 = 2 × 3 × 5 Att 2 Att 2 2, 3, 5, listed merits full marks. Blunders (-3) B1 Each correct prime constituent omitted and/or each incorrect prime constituent included. Misreadings (-1) M1 Write as sum of 3 primes (30 = 2 + 5 + 23) or (30 = 2 + 11 + 17). Attempts (2 marks) A1 Writes a prime number ∈ M. Worthless (0) W1 No prime number appears. Page 6 QUESTION 2 Part (a) Part (b) Part (c) Part (a) 2(a) 10 marks 20 (5, 10, 5) 20 (10, 5, 5) Att 3 Att 7 (2, 3, 2) Att7 (3, 2, 2) 10 marks €260 is shared between Mark and Una in the ratio 6:7. How much does each receive? Part (a) 10 marks Att 3 Att 3 " 6 parts : 7parts 13 Parts = 260 260 ⇒1 Part = = 20 13 Mark = 20 × 6 = 120 Una = 20 × 7 = 140 or 260 − 120 =140 6x : 7x ⇒13 x = 260 ⇒ x = 20 ⇒ 6 x = 120 ⇒ 7 x = 140 6 + 7 = 13 1 = 20 13 6 ⇒ =120 (Mark) 13 ⇒ 260 − 120 = 140 (Una) 7 = 140 13 ⇒ 260 −140 = 120 or 260 −140 =120 Blunders (-3) B1 B2 B3 B4 B5 B6 B7 " Correct answers without work. Divisor ≠ 13 only and continues. Incorrect multiplier or fails to multiply. (each time). Error in transposition. Fails to find second amount. Adds instead of subtracts.e.g.260 + 120 = 380 or 260 +140 = 400. Finds 6% of 260 (15 ⋅ 6) and 7% of 260 (18 ⋅ 2) Slips (-1) S1 Numerical errors to a max of 3. Misreadings (-1) M1 Interchanges Mark and Una. Attempts (3 marks) A1 A2 A3 A4 260 260 and/or and stops. 6 7 6 7 Indicates 6 parts or 7 parts or 13 parts or or or 6 + 7=13 and stops. 13 13 Indicates multiplication of 260 by 6 and/or 7 and stops. Both answers added together equal €260. (No work shown). Divisor ≠ 13 e.g. Worthless (0) W1 Incorrect answer without work. {Subject to A4}. Page 7 Part (b) (i) 2(b) (i) 5 marks Att 2 On a day when €1 = £ 0 ⋅ 68 , find the value in euro of £816. Part (b) (i) 5 marks Att2 " €1 = £ 0⋅ 68 €? = £816 ?= £ 0⋅ 68 = €1 1 ⎛ 25 ⎞ ⇒ £1 = € ⎜ ⎟ 0 ⋅ 68 ⎝ 17 ⎠ 816 = € 1200 0 ⋅ 68 ⇒ £816 = 816 × 1 = €1200 0 ⋅ 68 * No penalty for the omission of € or £ symbols. ⎛ 25 ⎞ ⎛ 13872 ⎞ ⎛ 1 ⎞ * Note: Natural Display calculator gives ⎜ ⎟. ⎟ = ⎜ ⎟ , 816 × 0 ⋅ 68 = ⎜ ⎝ 17 ⎠ ⎝ 25 ⎠ ⎝ 0.68 ⎠ Blunders (-3) " B1 B2 Correct answer without work. Incorrect operation. i.e. 816 × 0 ⋅ 68 = 554 ⋅ 88 0 ⋅ 68 68 or B3 Incorrect ratio . 816 81600 B4 Decimal error. 816 and stops. B5 Fails to finish, leaves as 0 ⋅ 68 Slips (-1) S1 Numerical errors to a max of 3. 1 =1 ⋅ 470588235 = 1 ⋅ 47 (€ 1199 ⋅ 52 ) or 1⋅ 5 (€1224 ) S2 Rounds off too early. e.g. 0 ⋅ 68 Attempts (2 marks) 1 A1 £1 = € 0 ⋅ 68 and stops. Worthless (0) W1 Adds or subtracts 816 to 0 ⋅ 68 and stops. W2 Incorrect answer without work. Page 8 Part (b) (ii) 10 marks 2(b) (ii) By rounding each of these numbers to the nearest whole number, 5 ⋅ 8 × 8 ⋅ 148 estimate the value of . 11 ⋅ 64 Att 3 Part (b) (ii) Att 3 " 10 marks 5 ⋅ 8 × 8 ⋅ 148 is approximately equal to 11 ⋅ 64 6 × 8 48 = * * 4 12 12 * = 6×8 and stops ⇒ 4 marks. 12 No penalty if the intermediate step between approximations and final answer is not 48 shown. i.e not shown. 12 5 ⋅ 8 × 8 ⋅ 148 ⎛ 203 ⎞ Special Case: = 4 ⋅ 06 . ⎜ ⎟ presented in this part ⇒ Attempt 3 marks. 11 ⋅ 64 ⎝ 50 ⎠ Blunders (-3) B1 Correct answer without work. B2 Error(s) in rounding off to the nearest whole number. (once only) B3 Decimal error in calculation of final value. B4 An arithmetic operation other than indicated. 6 8 48 B5 Error(s) in the manipulation of the denominator. e.g. . × = 12 12 144 6 × 8 3 × 4 12 = = =2 B6 Incorrect cancellation e.g. 12 6 6 " Slips (-1) S1 Numerical errors to a max of 3. Attempts (3 marks) A1 Only one or two approximations made to the given numbers and stops. Worthless (0) W1 Incorrect answer without work. Page 9 Part (b) (iii) 2(b) (iii) 5 marks Using a calculator, or otherwise, find the exact value of Part (b) (iii) * Att 2 Note: ⎛ 5.8 ⎞ ⎜ ⎟ ⎝ 11.64 ⎠ 5 ⋅ 8 × 8 ⋅ 148 . 11 ⋅ 64 5 marks 5 ⋅ 8 × 8 ⋅ 148 47 ⋅ 2584 ⎛ 203 ⎞ ⎛ 3 ⎞ = = 4 ⋅ 06 ⎜ ⎟ ⎜4 ⎟ 11 ⋅ 64 11 ⋅ 64 ⎝ 50 ⎠ ⎝ 50 ⎠ 145 ⎛ 8.148 ⎞ 7 , = ⎜ ⎟= . . 291 ⎝ 11.64 ⎠ 10 Att 2 Blunders (-3) B1 Decimal error. B2 B3 B4 B5 B6 B7 B8 47 ⋅ 2584 . 11 ⋅ 64 5 ⋅ 8 8 ⋅ 148 ⎛ 203 ⎞ × = 0 ⋅ 4982817869 × 0 ⋅ 7 = 0 ⋅ 3487972509 . ⎜ Treats as ⎟. 11 ⋅ 64 11 ⋅ 64 ⎝ 582 ⎠ 5 ⋅ 8 + 8 ⋅ 148 13 ⋅ 948 ⎛ 3487 ⎞ Reads as = = 1 ⋅ 198281787 . ⎜ ⎟. 11 ⋅ 64 11 ⋅ 64 ⎝ 2910 ⎠ 5 ⋅ 8 − 8 ⋅ 148 − 2 ⋅ 348 ⎛ − 587 ⎞ = Reads as = − 0 ⋅ 2017182131 . ⎜ ⎟. 11 ⋅ 64 11 ⋅ 64 ⎝ 2910 ⎠ 11 ⋅ 64 11 ⋅ 64 ⎛ 50 ⎞ = Treats as = 0 ⋅ 2463054187 . ⎜ ⎟. 5 ⋅ 8 × 8 ⋅ 148 47 ⋅ 2584 ⎝ 203 ⎠ 11 ⋅ 64 11 ⋅ 64 ⎛ 2910 ⎞ Treats as = = 0 ⋅ 8345282478. ⎜ ⎟. 5 ⋅ 8 + 8 ⋅ 148 13 ⋅ 948 ⎝ 3487 ⎠ 11 ⋅ 64 11 ⋅ 64 ⎛ − 2910 ⎞ Treats as = = − 4 ⋅ 957410562 . ⎜ ⎟. 5 ⋅ 8 − 8 ⋅ 148 − 2 ⋅ 348 ⎝ 587 ⎠ Leaves answer as Slips (-1) S1 Numerical errors to a max of 3. S2 Any rounding off. Attempts (2 marks) A1 Any correct relevant calculation and stops. ⎛ 5 ⋅ 8 ⎞ 145 = 0 ⋅ 4982817869 , e.g. 5 ⋅ 8 × 8 ⋅ 148 = 47.2584, ⎜ ⎟= ⎝ 11 ⋅ 64 ⎠ 291 Worthless (0) W1 Incorrect answer without work. Page 10 ⎛ 8 ⋅ 148 ⎞ 7 ⎜ ⎟ = =0⋅7. ⎝ 11 ⋅ 64 ⎠ 10 Part(c) (i) 10 marks Att 3 1 11 and as decimals. 5 50 Hence, or otherwise, put the following numbers in order, starting with the smallest and finishing with the largest: 1 11 0 ⋅ 25, , . 5 50 2(c) (i) Using a calculator, or otherwise, write Part(c) (i) 1 =0⋅ 2 5 10 marks 1 , 5 * Accept: * Accept: * Note: 11 , 50 0·2, 0·22, 0·25, merits 10 marks. 1 No penalty for writing 0·25 as . 4 1 11 or =0⋅ 2 = 0 ⋅ 22 5 50 Blunders (-3) B1 Fails to write a fraction as a decimal. B2 Writes fraction as incorrect decimal. B3 Decimal error. B4 Inverts fraction and continues. B5 Incorrect order or fails to order. Attempts (3 marks) 1 0 ⋅ 25 = and stops. A1 4 Worthless(0) W1 Att 3 11 = 0 ⋅ 22 50 0 ⋅ 25 0 ⋅ 25 , or . or similar. 5 50 Page 11 0·25, merits 4 marks Part(c) (ii) 2(c) (ii) 5 marks Att 2 Using a calculator, or otherwise, divide 1170 by 0⋅ 45 and express your answer in the form a ×10 n , where 1 ≤ a < 10 and n∈ N Part(c) (ii) " 5 marks Att 2 1170 ÷ 0 ⋅ 45 = 2600 = 2 ⋅ 6 × 10 3 Blunders (-3) " B1 B2 Correct answer without work. Decimal error. B3 ⎛ 1 ⎞ Inverts 0 ⋅ 45 ÷1170 = 0 ⋅ 00038 ⎜ ⎟. ⎝ 2600 ⎠ B4 ⎛ 1053 ⎞ Multiplies 1170 × 0 ⋅ 45 = 526 ⋅ 5 = 5 ⋅ 256 × 10 2 ⎜ ⎟. ⎝ 2 ⎠ Slips (-1) S1 Numerical errors to a max of 3. S2 Incorrect format, where a < 1 or a ≥ 10 and n ∉ N. S3 2600 and stops. Attempts (2 marks) A1 Any relevant step. e.g. Partial long division.e.g. A2 1 20 = 0 ⋅ 45 9 Page 12 1170 =2 0 ⋅ 45 Part(c) (iii) 2(c) (iii) 5 marks Using a calculator, or otherwise, evaluate 5 ⋅ 32 2 = (3 ⋅ 9) − × 1 ⋅ 81 0.64 Give your answer correct to two decimal places Part(c) (iii) 5 marks 5 ⋅ 32 = 15 ⋅ 21 − × 1 ⋅ 81 0⋅8 = 15 ⋅ 21 − 6 ⋅ 65 × 1 ⋅ 81 = 15 ⋅ 21 − 12 ⋅ 0365 ⎛ 6347 ⎞ = 3 ⋅ 1735 ⎜ ⎟ ⎝ 2000 ⎠ = 3 ⋅ 17 * Correct answer (without work) incorrectly rounded off ⇒ 2 marks. e.g. = 3 ⋅ 1735 , = 3 ⋅ 174 5.32 ⎛ 1521 ⎞ ⎛ 133 ⎞ 2 * Note: Natural Display calculator gives (3 ⋅ 9) = ⎜ =⎜ ⎟, ⎟, 0 ⋅ 64 ⎝ 20 ⎠ ⎝ 100 ⎠ Blunders (-3) Att 2 Att 2 " " B1 B2 Correct answer without work. Mishandles (3 ⋅ 9) 2 . B3 B4 B5 B6 B7 Mishandles 0 ⋅ 64 . Error in 5 ⋅ 32 ÷ 0 ⋅ 8 or 9 ⋅ 6292 ÷ 0 ⋅ 8 . Error in 5 ⋅ 32 × 1 ⋅ 81 or 6 ⋅ 65 × 1 ⋅ 81 . Decimal error. Subtracts before Division (15 ⋅ 21 − 5 ⋅ 32 ) ÷ 0 ⋅ 8 ×1 ⋅ 81 = 9 ⋅ 89 ÷ 0 ⋅ 8 × 1 ⋅ 81 = 22 ⋅ 376125 . B8 Subtracts before Multiplication (15 ⋅ 21 − 6 ⋅ 65) ×1 ⋅ 81 = 8 ⋅ 56 × 1 ⋅ 81 =15 ⋅ 4936 . B9 Use of mathematical operator other than that which is indicated. 5 ⋅ 32 = 27 ⋅ 5301 − 6 ⋅ 65 = 20 ⋅ 8801 = 20 ⋅ 88 . B10 Works as 15 ⋅ 21 × 1 ⋅ 81 − 0⋅8 ⎛ 5 ⋅ 32 ⎞ B11 Works as ⎜ ×1 ⋅ 81⎟ −15 ⋅ 21 =12 ⋅ 0365 −15 ⋅ 21 = − 3 ⋅ 1735 = − 3 ⋅ 17 . ⎝ 0⋅8 ⎠ Slips (-1) S1 Numerical errors to a max of 3. S2 Each premature rounding off that effects the final answer to a max of 3. S3 Fails to round off or rounds off incorrectly when giving final answer. 6347 S4 Leaves as . 2000 Attempts (2 marks.) A1 Any correct relevant step e.g. (3 ⋅ 9) 2 = 15 ⋅ 21 , 0 ⋅ 64 = 0 ⋅ 8 . Worthless (0) W1 Incorrect answer without work. (Note 1st *). Page 13 QUESTION 3 Part (a) Part (b) Part (c) 10 marks 20 (10, 10) marks 20 (5, 5, 5, 5,) marks Att 3 Att 6(3, 3) Att 8(2, 2, 2, 2) Part (a) 10 marks Att 3 3(a) Kate went to the cinema. She bought a ticket at €8·50 and then bought popcorn costing €4·40. How much change did Kate get from a €20 note? Part (a) 10 marks Att 3 " * €8 ⋅ 50 + €4 ⋅ 40 = €12 ⋅ 90 €20 ⋅ 00 − €12 ⋅ 90 = €7 ⋅ 10 * * * ** €20 ⋅ 00 − €8 ⋅ 50 = €11 ⋅ 50 €11 ⋅ 50 − €4 ⋅ 40 = €7 ⋅ 10 *** €20 ⋅ 00 − €4 ⋅ 40 = €15 ⋅ 60 €15 ⋅ 60 − €8 ⋅ 50 = €7 ⋅ 10 Accept 710c, ( 7 ⋅ 10 ) Final subtraction step subject to maximum deduction of 3 marks. No penalty for the omission of € symbol. Blunders (-3) B1 B2 B3 B4 B5 B6 " Correct answer without work. Calculates the cost of the ticket and the popcorn but fails to find the change. Fails to find total cost i.e. no addition. Operation other than subtraction when finding the change. Operation other than addition when finding total cost. Decimal error e.g. €1 ⋅ 29 (Note: 1st* above). Slips (-1) S1 Numerical errors to a max of 3. Attempts (3 marks) A1 Any attempt at addition /subtracation. Worthless (0) W1 Incorrect answer without work. W2 Multiplication or division of the given numbers. Page 14 Part (b) (i) 3(b) (i) 10 marks VAT at 13 ⋅ 5 % is added to a bill of €860 Calculate the total bill. Part (b) (i) Att3 10 marks Att3 " 860 100 860 113 ⋅ 5 % = × 113 ⋅ 5 100 = 8 ⋅ 60 × 113 ⋅ 5 13 ⋅ 5 100 13 ⋅ 5 VAT = × 860 100 ⎛ 1161 ⎞ = 116 ⋅ 10 ⎜ ⎟ ⎝ 10 ⎠ Total Bill = 860 + 116 ⋅ 10 Total Bill = € 976 ⋅ 10 Total Bill = € 976 ⋅ 10 100 % = 860 1% * = 13 ⋅ 5% = 860 ×1 ⋅ 135 Total Bill = € 976 ⋅ 10 € 116 ⋅ 10 without work and stops merits 4 marks. Blunders (-3) B1 B2 " B4 B5 Correct answer without work. Decimal error. 100 100 or and continues (giving answers 757 ⋅ 71 or 6370 ⋅ 37 ). Inverts as 113 ⋅ 5 13 ⋅ 5 Mishandles 13 ⋅ 5% e.g. 860 ×13 ⋅ 5 or 860 ÷13 ⋅ 5 . Note: {860 must be used}. 860 taken as 113 ⋅ 5 %. B6 No addition of VAT (as per candidates work) to the bill. B7 Subtraction of VAT ( as per candidates work) from the bill. B3 Slips (-1) S1 Numerical errors to a max of 3. Misreadings (-1) M1 Reads as 15·3% or €680. Attempts (3 marks) 13 ⋅ 5 860 and stops. A1 and stops. or 100 100 A2 100% = 860 and stops. 13 ⋅ 5 860 A3 100 × and stops. or and stops. 860 13 ⋅ 5 A4 860 + 13 ⋅ 5% and stops. Worthless (0) W1 Incorrect answer without work. W2 860 + 13 ⋅ 5 = 873 ⋅ 5 and stops or continues. Page 15 Part (b) (ii) 3(b) (ii) 10 marks €4750 is invested at 3 ⋅ 7 % per annum What is the amount of the investment at the end of one year? Part (b) (ii) 10 marks Att 3 Att 3 " 4750 100 4750 3⋅ 7 % = × 3⋅7 100 1%= ⎛ 703 ⎞ Interest = 175 ⋅ 75 . ⎜ ⎟ ⎝ 4 ⎠ Amount = 4750 + 175 ⋅ 75 P×R 100 4750 × 3 ⋅ 7 I = 100 Interest = 175 ⋅ 75 I = Amount = 4750 ×1 ⋅ 037 ⎛ 19703 ⎞ Amount= € 4925 ⋅ 75 ⎜ ⎟ ⎝ 4 ⎠ Amount = € 4925 ⋅ 75 Amount = € 4925 ⋅ 75 * € 175 ⋅ 75 (without work) and stops ⇒ 4 marks. Blunders (-3) B1 B2 B3 B4 B5 B6 B7 Correct answer without work. " 4750 × 100 {No penalty if already penalised in b (i)} Mishandles 3 ⋅ 7 %. e.g. 3⋅7 Decimal error (once only). Stops at interest i.e. fails to calculate amount. Subtracts to calculate amount. 4750 Mathematical error(s) working with ×3 ⋅ 7 . 100 1⋅ 037 treated as 1⋅ 37 . Slips (-1) S1 Numerical errors to a max of 3. Misreadings (-1) M1 Reads as €4570. M2 3 ⋅ 7% written as 7 ⋅ 3%. Attempts (3 marks) A1 Correct formula with or without substitution and stops. A2 Some use of 100 in attempt to find percentage e.g. 3 ⋅ 7 % = A3 4750 + 3 ⋅ 7 % and stops. Worthless (0) W1 Incorrect answer without work. W2 4750 + 3 ⋅ 7 = 4753⋅ 7 and stops or continues. Page 16 3⋅7 or 1⋅ 03 7 and stops. 100 Part (c) 20 (5, 5, 5, 5) marks Att 8 (2, 2, 2, 2) 3(c) Darragh’s annual wage is €48 000. He pays income tax at the rate of 20% on the first €34000 of his wage and income tax at the rate of 41% on the remainder of his wage. Darragh has an annual tax credit of €3600. Part (c) (i) 5 marks Find the tax on the first €34000 of his wage, calculated at the rate of 20%. 3(c) (i) Att 2 Part (c) (i) Att 2 5 marks " 100% = 34000 1% = 340 20% = 6800 Tax = €6800 * 34000 × 20 100 Tax = €6800 Tax = Tax = 34000 × 0 ⋅ 2 Tax = €6800 1 5 34000 ÷ 5 Tax = €6800 20 % = No penalty for missing € symbol. Blunders (-3) B1 B2 B3 B4 Correct answer without work. " Mishandles 20%, e.g. 34000 × 20 = 680000 or 34000 ÷ 20 =1700 Uses €48000 instead of €34000. Decimal error. Slips (-1) S1 Numerical errors to a max of 3 Attempts (2 marks) A1 A2 A3 Some use of 100 in attempt to find percentage e.g. 20% = 1 5 Writes 34000 + 20% and stops. 20 % = Worthless (0) W1 Incorrect answer without work Page 17 20 or 0 ⋅ 2 and stops. 100 Part (c) (ii) 3(c) (ii) 5 marks Att 2 Find the tax on the remainder of his wage, calculated at the rate of 41%. Part (c) (ii) " (ii) 100% = 14 000 5 marks Remainder of wage = €48 000 − €34 000= €14,000 Tax = 14 000 × 0 ⋅ 41 14 000 Tax = × 41 = 5 740 100 1% = 140 41% = 5740 Tax = 5740 * Att 2 Tax = 5 740 No penalty for missing € symbol. Blunders (-3) B1 B2 B3 B4 " Correct answer without work. Mishandles 41%, e.g. 14 000 ÷ 41 [No penalty if already penalised in (c) (i)]. Does not use €14 000. Decimal error. Slips (-1) S1 Numerical errors to a max of 3. Attempts (2 marks) A1 Some use of 100 in attempt to find percentage e.g. 41% = A2 48 000 - 34 000 or 14 000 and stops. Worthless (0) W1 Incorrect answer without work. Page 18 41 = 0 ⋅ 41 and stops. 100 Part (c) (iii) 3(c) (iii) 5 marks Hence calculate Darragh’s gross tax. Att 2 Part (c) (iii) 5 marks Att 2 " * * (iii) Darragh’s gross tax = €6800 + €5740 = €12 540 Allow candidates incorrect answers from parts (i) and (ii). No penalty for missing € symbol. Blunders (-3) B1 B2 B3 " Correct answer without work. Subtracts to find gross tax e.g. €6800 − €5740 = €1060 Misuse of tax credit. Slips (-1) S1 Numerical errors to a max of 3. Attempts (2) A1 Answer from c (i) and /or c (ii) written in this part. Worthless (0) W1 Incorrect answer without work Part (c) (iv) 3(c) (iv) 5 marks Calculate Darragh’s take home pay. Att 2 Part (c) (iv) 5 marks Att 2 " * * Tax due = €12 540 - €3600 = €8940 Take home pay = €48 000 - €8940 Take home pay = €39 060 Allow candidate’s incorrect gross tax figure from (c) (iii). No penalty for missing € symbol. Blunders (-3) B1 B2 B3 Correct answer without work. " Misuse or no use of tax credit e.g. €12 540 + €3600 Decimal error. Slips (-1) S1 Numerical errors to a max of 3. Attempts (2) A1 Answer from c (iii) written in this part. Worthless (0) W1 Incorrect answer without work. Page 19 QUESTION 4 Part (a) Part (b) Part (c) 10 (5, 5) marks 20 (10, 10) marks 20 (5, 5, 5, 5) marks Part (a) 4(a) 10(5, 5) marks If a = 5 and b = 7, find the value of: " (i) " (ii) Part (a) (i) 4(a) (i) * ab + 13 5 marks If a = 5 and b = 7, find the value of: (i) 9a + b (i) 45 + 7 ⇒ 4 marks. 5 marks 9a + b = 9(5) + 7 = 45 + 7 = 52 Blunders (-3) B1 B2 B3 B4 B5 B6 Att 4(2,2) 9a + b Part (a) (i) " Att 4(2, 2) Att 6(3, 3) Att 8(2, 2, 2, 2) " Correct answer without work. Leaves 9(5) in the answer. Incorrect substitution and continues Breaks order i.e. [ 9(5 + 7 ) = 9(12 ) = 108 ]. Treats 9(5) as 14 or 95. Combines 9a + b to give 9ab and continues. Slips (-1) S1 Numerical errors to a max of 3. S2 Treats as 9a − b . S3 Treats as 9b + a . Attempts (2 marks) A1 Substitutes for either a or b and stops e.g. 9(5). A2 Writes 7 or 5 in this part. A3 Any correct step. Worthless (0) W1 Incorrect answer with no work. W2 Writes as 9ab and stops. Page 20 Att 2 Att 2 Part (a) (ii) 4(a) (ii) 5 marks If a = 5 and b = 7, find the value of: (ii) ab + 13 Part (a) (ii) 5 marks " ab + 13 = 5(7 )+13 = 35 + 13 = 48 * 35 + 13 ⇒ 4 marks. Blunders (-3) B1 B2 B3 B4 B5 B6 Correct answer without work. " Leaves 5(7) in the answer. Incorrect substitution and continues Breaks order i.e. [ 5(7 + 13) = 5(20 ) = 100 ]. Treats 5(7) as 12 or 57. Combines ab + 13 to give 13ab and continues. Slips (-1) S1 Numerical errors to a max of 3. S2 Treats as ab −13 . Attempts (2 marks) A1 Substitutes for either a or b and stops e.g. a (7). A2 Writes 7 or 5 in this part. A3 Any correct step. Worthless (0) W1 Incorrect answer with no work. W2 Writes as 13ab and stops. Page 21 Att 2 Att 2 Part (b) (i) 4(b) (i) 10 marks Att 3 Solve the equation 3(2 x −1) = 4 x + 9 Part (b) (i) 10 marks " Att 3 3(2 x − 1) = 4 x + 9 6x − 3 = 4x + 9 6x − 4x = 3 + 9 2 x = 12 12 2 x=6 x = Blunders (-3) B1 B2 B3 B4 B5 " Correct answer without work. ( x = 6 stated or substituted) Error in distributive law and continues. e.g. 6 x − 1 = 4 x + 9 Error in transposition. (each time). Combines “x's”to “numbers” and continues. e.g. 6 x − 3 = 3x or 4 x + 9 = 13 or 2 x −1 = x Stops at 2 x = 12 or similar. Slips (-1) S1 Numerical errors to a max of 3. 12 or similar. S2 Leaves as x = 2 Attempts (3 marks) A1 Any substitution for values of x other than x = 6 . A2 Any correct step. e.g. (2 x −1) = 4 x + 9 3 Worthless (0) W1 Combines “x's” to “numbers” and stops W2 Incorrect answer with no work. Page 22 Part (b) (ii) 4(b) (ii) 10 marks Multiply (5 x − 2) by (3x + 4) . Write your answer in its simplest form. Part (b) (ii) 10 marks Att 3 Att 3 " (5 x − 2)(3x + 4) (3x + 4)(5 x − 2) 15 x + 20 x − 6 x − 8 15 x − 6 x + 20 x − 8 (5 x − 2)(3x + 4) 5 x(3 x + 4 ) − 2(3 x + 4 ) 15 x 2 + 14 x − 8 15 x 2 + 14 x − 8 15 x 2 + 20 x − 6 x − 8 2 2 15 x 2 + 14 x − 8 * 15 x 2 + 20 x − 6 x − 8 merits 7 marks. Blunders (-3) B1 B2 B3 B4 " Correct answer without work. Error in distribution. Combines “x's”to “numbers” and continues. e.g. 5 x − 2 = 3 or 3x + 4 = 7 x . Fails to group or groups incorrectly. Slips (-1) S1 Numerical errors to a max of 3. Attempts (3 marks) A1 Any correct multiplication. e.g. 15 x . A2 Any correct grouping of terms. A3 A correct step. A4 Substitutes a value of “ x ” and continues correctly. A5 Treats as (5 x − 2 ) ± (3x + 4 ) to give 8 x + 2 or 2 x − 6. Worthless (0) W1 Combining unlike terms and stops. W2 No distribution but A2 or A5 may apply to subsequent work e.g. gathering of terms. Page 23 Part (c) 20 (5, 5, 5, 5) marks 4(c) Shane is x years old. Eileen is three years younger than Shane. Att 8 (2, 2, 2, 2) Part (c) (i) 5 marks 4(c) (i) Find Eileen's age in terms of x . Att 2 Part (c) (i) Att 2 5 marks x −3 * Algebraic work required to earn marks. Blunders (-3) B1 Incorrect expression of Eileen's age other than mireadings below. Misreadings (-1) M1 Answer given as x + 3 . M2 Answer given as 3 x . Attempts (2 marks) A1 Any effort at forming an expression.e.g. Eileen’s age = y . Worthless (0 marks) W1 Eileen's age given as a constant or x . W2 Inequality appears. Part (c) (ii) 5 marks If the sum of Shane’s age and Eileen’s age is 47, write down an 4(c) (ii) equation in x to represent this information. Att 2 Part (c) (ii) Att 2 * 5 marks x + x − 3 = 47 Accept candidates answer from previous work. Blunders (-3) B1 Error in forming equation. Attempts (2 marks) A1 Answer from part c (i) written down and stops. A2 Any effort at forming an expression. A3 Writes Shane's age and stops. i.e. x Page 24 Part (c) (iii) 4(c) (iii) 5 marks Solve the equation that you formed in part (ii) above, for x. Part (c) (iii) 5 marks x + x − 3 = 47 2 x = 47 + 3 2 x = 50 " 50 2 x = 25 x= * Accept candidates answer from previous work. Blunders (-3) B1 B2 B3 B4 B5 " ( x = 25 stated or substituted) Correct answer without work. Error in transposition. Error in grouping terms or fails to group. Combines “x's”to “numbers” and continues. e.g. x + x − 3 = − x Stops at 2 x = 50 or similar. Slips (-1) S1 Numerical errors to a max of 3. 50 or similar. S2 Leaves as x = 2 Attempts (2 marks) A1 Any substitution for values of x other than x = 25 . A2 Answer from part c(ii) written down and stops. A3 Any effort at solving equation. A4 Any correct step. Worthless (0) W1 Combines “x's” to “numbers” and stops. ( Note A3 above) W2 Incorrect answer with no work. Page 25 Att 2 Att 2 Part (c) (iv) 4(c) (iv) 5 marks Att 2 When Eileen is 2 x + 5 years old, find the sum of Shane’s age and Eileen’s age Part (c) (iv) 5 marks " Eileen's age → 2 x + 5 = 2(25) + 5 = 50 + 5 = 55 Shane's age → 55 + 3= 58 Sum of Shane's age and Eileen's age = 55 + 58 = 113 * Att 2 Allow Eileen's age = 2 x + 5 Shane's age = 2 x + 8 Sum of Shane's age and Eileen's age = 2 x + 5 + 2 x + 8 = 4 x + 13 Accept candidates answer from previous work. Blunders (-3) B1 B2 B3 B4 " Correct answer without work. Error in grouping terms or fails to group. Combines “x's”to “numbers” and continues. e.g. 2 x + 5 + 2 x + 8 = 7 x + 10 . Only one age calculated. Misreadings (-1) M1 Takes Shane's age as x and continues 2 x + 5 + x = 3x + 5 . Slips (-1) S1 Numerical errors to a max of 3. S2 Leaves as 55 + 58 or similar. Attempts (2 marks) A1 Any correct step. A2 Writes answer from c (iii) and stops. Worthless (0) W1 Incorrect answer with no work. W2 Works with 2 x + 5 = 47 Page 26 QUESTION 5 Part (a) Part (b) Part (c) 5 marks 20(5, 5, 5, 5) marks 25(5, 5, 15) marks Part (a) 5 marks Att 2 Find the values of x for which 3x + 2 ≤ 8, x ∈ N 5 (a) Part (a) " Att 2 Att 8(2, 2, 2, 2) Att 9(2, 2, 5) 5 marks Att 2 3x + 2 ≤ 8 3x ≤ 8 − 2 or 3x ≤ 6 x≤2 {0 ,1, 2} 0 1 2 Blunders (-3) B1 B2 B3 B4 B5 " Correct answer without work. Error in transposition. Combines “x's” to “numbers”. e.g.. 5 x ≤ 8 and continues. Mishandles the direction of inequality e.g. 3x ≥ 6 Treats inequality as equality and continues. Slips (-1) S1 Numerical errors to a max of 3. S2 ≤ taken as < S3 Each missing or incorrect value of x subject to a max of 3. Misreadings (-1) M1 2 x + 3 ≤ 8 , and continues. Attempts (2 marks) A1 Attempt at transposition and stops. A2 0, 1 or 2 substituted for x . A3 Number line with one or more of the correct elements clearly indicated. (Ignore arrows) Worthless (0) W1 Incorrect answer with no work.e.g.{1, 2, 3, 4, 5, 6, 7, 8,…..}. Page 27 Part (b) (i) 5(b) (i) 5 marks Factorise: Part (b) (i) Att 2 4 a + ab 5 marks a (4 + b ) Att 2 Blunders (-3) B1 Removes factor incorrectly. Attempts (2 marks) A1 Indication of common factor. e.g. underline a 's and stops. Part (b) (ii) 5(b) (ii) Factorise: Part (b) (ii) " * 5 marks 2 x − 2 y + cx − cy Att 2 5 marks Att 2 2 x − 2 y + cx − cy 2 x − 2 y + cx − cy or x(2 + c ) − y (2 + c ) 2( x − y ) + c ( x − y ) (2 + c )(x − y ) (x − y )(2 + c ) Accept also (with or without brackets) for 5 marks any of the following (2 + c ) and (x − y ) [The word and is written down.] (2 + c ) or (x − y ) [The word or is written down.] (2 + c ) , (x − y ) [A comma is used] Blunders (-3) B1 B2 B3 B4 " Correct answer without work. Stops after first line of correct factorisation. e.g. 2(x − y ) + c(x − y ) or equivalent. Error(s) in factorising any pair of terms. Incorrect common factor and continues. e.g. y (− 2 − c ) + x(2 + c ) Slips (-1) S1 (2 + c ) ± ( x − y ) S2 Correct first line of factorisation but ends as 2c( x − y ) or xy(2 + c ) . Attempts (2 marks) A1 Pairing off, or indication of common factors and stops. A2 Correctly factorises any pair and stops. Page 28 Part (b) (iii) 5(b) 5 marks Att 2 x − 2 x − 24 2 Factorise: (iii) Part (b) (iii) 5 marks Att 2 x 2 − 2 x − 24 x +4 x 2 − 6 x + 4 x − 24 x( x − 6 ) + 4( x − 6 ) (x + 4)(x − 6) x −6 * − (− 2 ) ± (− 2)2 − 4(1)(− 24) 2(1) 2 ± 10 2 ± 4 + 96 = 2 2 12 −8 = 6 and =− 4 2 2 ⇒ ( x − 6 )( x + 4 ) ⇒ ( x + 4 )( x − 6 ) Accept also (with or without brackets) for 5 marks any of the following (x − 6) and (x + 4) [The word and is written down.] (x − 6) or (x + 4) [The word or is written down.] (x − 6) , (x + 4) [A comma is used] Blunders (-3) B1 Incorrect two term linear factors of. x 2 − 2 x − 24 formed from correct (but inapplicable) factors of x 2 and − 24 .e.g ( x − 12 )( x + 2 ) . B2 Incorrect factors of x 2 . B3 Incorrect factors of − 24 . B4 Correct cross method but factors not shown and stops. B5 x( x − 6 ) + 4( x − 6 ) or similar and stops. B6 Incorrect common factor and continues. B7 Incorrect quadratic formula and continues. B8 Error in quadratic formula. B9 Answer left as roots. B10 Sign error in substituted formula. B11 Error in square root or square root ignored. Slips (-1) S1 Numerical errors to a max of 3. S2 (x + 4 ) ± ( x − 6 ) . Attempts (2 marks) A1 Correct quadratic equation formula quoted and stops A2 Correct factors of either x 2 or ± 24. A3 Any correct step. Worthless (0 marks) W1 x 2 − 2 x = 24 or similar and stops. W2 Combines “x's”to “numbers” and continues or stops. Page 29 Part (b) (iv) 5(b) 5 marks 144 − y 2 Factorise: (iv) Att 2 Part (b) (iv) * * * 5 marks (12 − y )(12 + y ) Accept also (with or without brackets) for 5 marks any of the following (12 − y ) and (12 + y ) [The word and is written down.] (12 − y ) or (12 + y ) [The word or is written down.] (12 − y ) , (12 + y ) [A comma is used] Quadratic equation formula method is subject to slips and blunders. 144 − y 144 + y merits 5 marks. ( )( Att 2 ) Blunders (-3) B1 Incorrect two term linear factors of 144 − y 2 formed from correct (but inapplicable) factors of 144 and − y 2 .e.g (144 − y )(1 + y ) . B2 Incorrect factors of 144 . B3 Incorrect factors of − y 2 . B4 ( y − 12 )( y + 12 ) . B5 (144 + y )(144 − y ) . B6 Answer left as roots. ( y = ± 12 ) Slips (-1) S1 (12 − y ) ± (12 + y ) Attempts (2 marks) A1 Correct factors of 144 only. A2 Correct factors of ± y 2 only. A3 ±12 or ± y appears. A4 144 − y 2 = (12)(12) − ( y ) y and stops. A5 A6 A7 Mention of the difference of two squares .e.g. { (144) − y 2 } Correct quadratic equation formula quoted and stops. 144 2 Worthless (0 marks) W1 Combines “y's” to “numbers” and continues or stops. Page 30 Part(c) (i) 5(c)(i) 5 marks x −1 x − 2 – as a single fraction 5 7 and give your answer in its simplest form. Express Part(c) (i) 5 marks " Att2 x −1 x−2 − 5 7 7( x − 1) − 5( x − 2 ) 35 7 x − 7 − 5 x + 10 35 2x + 3 35 Blunders (-3) B1 Correct answer without work. " B2 Error(s) in distribution. e.g. 7( x − 1) = 7 x − 1 B3 Mathematical error e.g. -7 +10 = -3. 2(-1) = 2. B4 Incorrect common denominator and continues. B5 Incorrect numerator from candidate's denominator e.g. B6 B7 No simplification of numerator. Omitting denominator. Slips (-1) S1 Drops denominator. S2 Numerical error to a max of 3. S3 Att 2 Answer not in simplest form. e.g. 4x + 6 . 70 Attempts (2 marks) A1 35 only or a multiple of 35 only appears. A2 Any correct step. Worthless (0) ⎛ x − 1 ⎞⎛ x − W1 ⎜ ⎟⎜ ⎝ 5 ⎠⎝ 7 x − 1 x − W2 5 2⎞ ⎟ and stops. ⎠ − 2 2x − 3 = 7 −2 Page 31 5( x −1) − 7( x − 2) . 35 Part(c) (ii) 5(c) (ii) 5 marks Hence, or otherwise, solve the equation Part(c) (ii) " Att2 x −1 x − 2 − =1 5 7 5 marks 2x + 3 35 2x + 3 2x 2x = 1 = 35 = 35 − 3 = 32 32 2 x = 16 x= * Accept candidates answer from previous work. Blunders (-3) B1 B2 " Correct answer without work. Error in transposition. (each time) Slips (-1) S1 Numerical error to a max of 3. 32 S2 Leaves as . 2 Attempts (2 marks) A1 Answer from (c) (i) written in this part or worked again in this part. A2 Any correct step and stops. Page 32 Att2 Part(c) (iii) 5(c) (iii) 15 marks Solve for x and for y: Att 5 3x + 2 y = 73 4 x + y = 59 . Part(c) (ii) 15 marks Att 5 " 3 x + 2 y = 73 4 x + y = 59 I II 2 y = 73 − 3 x 73 − 3 x 4 x + y = 59 y = 2 3 x + 2 y = 73 12 x + 8 y = 292 ⎛ 73 − 3 x ⎞ − 8 x − 2 y = − 118 − 12 x − 3 y = − 177 4x + ⎜ ⎟ = 59 ⎝ 2 ⎠ − 5 x = − 45 5 y = 115 8 x + 73 − 3 x = 118 5 x = 45 115 y = = 23 5 x = 118 − 73 5 45 x= =9 5 x = 45 ⇒ x=9 5 45 ⇒ y = 23 x= =9 5 ⇒ y = 23 * Apply only one blunder deduction (B2 or B3) to any error(s) in establishing the first equation in terms of x only or the first equation in terms of y only. * Finding the second variable is subject to a maximum deduction of (3). Blunders (-3) B1 B2 B3 B4 B5 B6 B7 3x + 2 y = 73 " Correct answers without work. Error(s) in establishing the first equation in terms of x only [ 5 x = 45 ]or the first equation in terms of y only [ 5 y =115 ] through elimination by cancellation. Error(s) in establishing the first equation in terms of x only [ 5 x = 45 ]or the first equation in terms of y only [ 5 y =115 ] through elimination by substitution. Errors in transposition in solving the first one variable equation. Errors in transposition when finding the second variable. Incorrect substitution when finding second variable. Finds one variable only. Slips (-1) S1 Numerical errors to a max of 3 Attempts (5 marks) A1 Attempt at transposition and stops. A2 Multiplies either equation by some number and stops . Worthless (0 marks) W1 Incorrect values for x or y substituted into the equations. Page 33 QUESTION 6 Part (a) Part (b) Part (c) 10 (5, 5) marks 25 (15, 10) marks 15 (5, 5, 5) marks Part (a) 6 (a) 10(5, 5) marks f (x) = 3x – 1. (i) f (5) (ii) f (−4) Part (a) (i) 6(a) (i) f (x) = 3x – 1. Part (a) (i) (i) Att 4(2, 2,) Att 8(5, 3) Att 6(2, 2, 2) Att 4(2, 2) Find: 5 marks Att 2 5 marks f (5) = 3(5) −1 = 15 − 1 = 14 Att2 Find: f (5) Blunders (-3) B1 Leaves 3(5) in the answer B2 Combines “x's”to “numbers” and continues e.g. 3x − 1 = 2 x = 2(5) = 10 B3 Mathematical error. e.g. 15 −1 = − 14 B4 Breaks order i.e. 3(5 − 1) = 3(4 ) = 12 Slips (-1) S1 Numerical errors to a max of 3. S2 Leaves x in the answer e.g. 14 x Misreadings (-1) M1 Correct substitution of any number other than 5 and continues. Attempts (2marks) A1 Substitutes for x and stops. i.e. 3(5) A2 Treats as equation and continues or stops. i.e. 3x −1 = 5 Worthless (0) W1 Combines “x's”to “numbers” and stops. W2 Ignores x giving 3 −1 = 2. W3 5[ f ( x )] = 15 x − 5 W4 Replaces coefficient i.e. 3 x → 5 x . W5 Incorrect answer without work. Page 34 Part (a) (ii) 6(a) (ii) f (x) = 3x – 1. Part (a) (ii) (ii) Find: 5 marks f (−4) 5 marks f (− 4) = 3(− 4) −1 = − 12 − 1 = − 13 Blunders (-3) B1 Leaves 3(− 4 ) in the answer B2 Combines “x's”to “numbers” and continues e.g. 3x − 1 = 2 x = 2(− 4) = − 8 B3 Mathematical error. e.g. − 12 − 1 =13 B4 Breaks order i.e. 3(− 4 − 1) = 3(− 5) = − 15 Slips (-1) S1 Numerical errors to a max of 3. S2 Leaves x in the answer e.g. − 13x . Misreadings (-1) M1 Correct substitution of any negative number other than − 4 and continues. Attempts (2marks) A1 Substitutes for x and stops. i.e. 3(− 4 ) A2 Treats as equation and continues or stops i.e. 3x − 1 = − 4 Worthless (0) W1 Combines “x's”to “numbers” and stops. W2 Ignores x giving 3 −1 = 2. W3 − 4[ f ( x )] = − 12 x − 4 . W4 Replaces coefficient .i.e. 3 x → − 4 x . W5 Incorrect answer without work. Page 35 Att 2 Att2 Part (b) 6(b) 25 (15, 10) marks Draw the graph of the function f : x → x 2 − 3x − 1 in the domain −1 ≤ x ≤ 4, where x ∈ R Part (b) Table f (x ) = f (− 1) = * f (0 ) = f (1) = f (2 ) = f (3) = f (4 ) = Att 8 (5, 3) 15 marks x2 (− 1)2 (0)2 (1)2 (2)2 (3)2 (4)2 − 3x -1 − 3(− 1) -1 = 3 − 3(0 ) -1 = -1 − 3(1) -1 = -3 − 3(2 ) -1 = -3 − 3(3) -1 = -1 − 3(4 ) -1 = 3 x x2 − 3x −1 f (x ) Att 5 -1 1 3 -1 3 0 0 0 -1 -1 1 1 -3 -1 -3 2 4 -6 -1 -3 Error(s) in each row /column attract a maximum deduction of 3. Blunders (-3) B1 “ − 3x ” taken as “ − 3 ”all the way. [In row headed − 3x by candidate] B2 “ − 1 ” calculated as “ − x ” all the way.[In row headed “ − 1 ” by candidate] B3 Adds in top row when evaluating f (x) . B4 Omits “ − 1 ” row. B5 Omits“ − 3 x ”row. B6 Omits a value in the domain (each time). B7 Each incorrect image without work. Slips (-1) S1 Numerical errors to a max of 3 in any row / column. Misreadings (-1) M1 Misreads “ x 2 ” as “ − x 2 ” and places “ − x 2 ” in the table or function M2 Misreads “ − 3 x ”as “ 3 x ”and places “ 3 x ”in the table or function. M3 Misreads “ − 1 ” as “ 1 ” and places “ 1 ” in the table or function Attempts (5 marks) A1 Omits “ x 2 ” row from table or treats “ x 2 ” as ± 2 x . A2 Any effort at calculating point(s). A3 Only one point calculated and stops. Page 36 3 9 -9 -1 -1 4 16 -12 -1 3 Part (b) Graph 10 marks Att 3 " 4 3 2 1 0 -2 -1 0 1 2 3 4 5 -1 -2 -3 -4 * * * * Accept candidate's values from previous work. Only one correct point graphed correctly ⇒ Att 5 + Att 3 Correct graph but no table ⇒ full marks i.e. (15+10) marks. Accept reversed co-ordinates if (i) if axes not labelled or (ii) if axes are reversed to compensate (see B1 below) Blunders (-3) B1 Reversed co-ordinates plotted against non-reversed axes (once only) {See 4th * above}. B2 Scale error (once only). B3 Points not joined or joined in incorrect order (once only). Slips (-1) S1 Each point of candidate graphed incorrectly. {Tolerance ± 0.25 } S2 Each point from table not graphed [See 2nd * above]. Attempts (3 marks) A1 Axes drawn (need not be labelled). A2 Some effort to plot a point{See 2nd * above}. Page 37 Part(c) (i) 6(c) (i) 5 marks Given that y = x + 2, complete the table below Part(c) (i) * Att 2 5 marks Att 2 x -1 0 1 2 y 1 2 3 4 Accept candidate's values without work. Slips(-1) S1 Each “ y ” value omitted or incorrect. Misreadings (-1) M1 Misreads y = x + 2 as y = x − 2 . Attempts(2marks) A1 Any one correct “ y ” value. A2 Any effort at calculating points. Worthless (0) W1 Copies x values into y row. W2 All y values incorrect with no work shown. (See M1 above). Page 38 Part(c) (ii) 6(c) (ii) 5 marks Att 2 On the grid below, the graph of the line y = 4 − x is drawn. Using your answers from (i), draw the graph of y = x + 2 on the same grid. Part(c) (ii) Graph 5 marks Att 2 5 4 3 2 y=x+2 1 y=4-x 0 -2 -1 0 1 2 3 4 -1 * Accept candidate's values from previous work. Blunders (-3) B1 Reversed co-ordinates ( y , x ) plotted. B2 Points not joined or joined in incorrect order. Slips (-1) S1 Each point of candidate graphed incorrectly. {See B1} S2 Each point from table not graphed or not contained on the candidate’s graph. Attempts (2 marks) A1 Any one correct point plotted. Worthless (0) W1 No correct point plotted. (See B1 above). Page 39 5 Part(c) (iii) Intersection 5 marks Att2 6(c) (iii) Use the graphs drawn in 6 (c) (ii) to write down the coordinates of the point of intersection of the two lines y = 4 − x and y = x + 2 . Part(c) (iii) Intersection " * 5 marks Point of intersection = (1, 3) Accept correct answer based on candidate's graph fully plotted. i.e. 4 points correctly plotted from c(i) otherwise attempt marks at most. Blunders(-3) B1 Answer not presented in designated box. B2 Answer beyond tolerance. {Tolerance ± 0.25 }. B3 Reversed co-ordinates ( y , x ) plotted. Attempts(2marks) A1 Point of intersection highlighted on graph. Worthless(0) W1 Answers outside of tolerance without graphical indication. W2 Incorrect answer from candidate's graph. Page 40 Att2 MARKING SCHEME JUNIOR CERTIFICATE EXAMINATION 2007 MATHEMATICS - ORDINARY LEVEL - PAPER 1 GENERAL GUIDELINES FOR EXAMINERS 1. Penalties of three types are applied to candidates’ work as follows: • Blunders - mathematical errors/omissions (-3) • Slips- numerical errors (-1) • Misreadings (provided task is not oversimplified) (-1). Frequently occurring errors to which these penalties must be applied are listed in the scheme. They are labelled: B1, B2, B3,…, S1, S2,…, M1, M2,…etc. These lists are not exhaustive. 2. When awarding attempt marks, e.g. Att(3), note that • any correct, relevant step in a part of a question merits at least the attempt mark for that part • if deductions result in a mark which is lower than the attempt mark, then the attempt mark must be awarded • a mark between zero and the attempt mark is never awarded. 3. Worthless work is awarded zero marks. Some examples of such work are listed in the scheme and they are labelled as W1, W2,…etc. 4. The phrase “hit or miss” means that partial marks are not awarded – the candidate receives all of the relevant marks or none. 5. The phrase “and stops” means that no more work is shown by the candidate. 6. Special notes relating to the marking of a particular part of a question are indicated by an asterisk. These notes immediately follow the box containing the relevant solution. 7. The sample solutions for each question are not intended to be exhaustive lists – there may be other correct solutions. 8. Unless otherwise indicated in the scheme, accept the best of two or more attempts – even when attempts have been cancelled. 9. The same error in the same section of a question is penalised once only. 10. Particular cases, verifications and answers derived from diagrams (unless requested) qualify for attempt marks at most. 11. A serious blunder, omission or misreading results in the attempt mark at most. 12. Do not penalise the use of a comma for a decimal point, e.g. €5.50 may be written as €5,50. Page 1 QUESTION 1 Part (a) Part (b) Part (c) Part (a) (i) 1(a) (i) 10(5, 5) marks 20(5, 5, 5, 5) marks 20(5, 5, 5, 5) marks Att 4(2, 2) Att 8(2, 2, 2, 2) Att 8(2, 2, 2, 2) 5 marks Att 2 Using the Venn diagram below, shade in the region that represents A ∪ B. A B Part (a) (i) 5 marks A Att 2 B Blunders (-3) B1 Any incorrect indication other than the misreading below. Misreadings (-1) M1 A ∩ B indicated. Page 2 Part (a) (ii) 5 marks Att 2 1(a) (ii) Using the Venn diagram below, shade in the region that represents A ∩ B. A B Part (a) (ii) 5 marks A Att 2 B Blunders (-3) B1 Any incorrect indication other than the misreading below. Misreading (-1) M1 A∪ B indicated. Page 3 Part (b) 1(b) U is the universal set 20(5, 5, 5, 5) marks Att(2,2,2,2) P P = {4, 7, 8} 4• •7 R = {1, 2, 3, 6, 7} •5 •8 Q = {1, 2, 5, 7, 8} •3 1• •2 6• R Part (b) (i) 1(b) (i) List the elements of: P ∪ Q. Part (b) (i) Q •9 5 marks 5 marks P ∪ Q = {1, 2, 4, 5, 7, 8.} Att 2 Att 2 Blunders (-3) B1 Any incorrect set of elements of P and Q other than the misreading as below. Misreadings (-1) M1 P ∩ Q giving {7, 8}. Attempts ( 2 marks) A1 3 or 6 or 9 appear in the answer. Part (b) (ii) 1(b) (ii) List the elements of: P \ R. Part (b) (ii) 5 marks Att 2 5 marks P \ R = { 4, 8} Att 2 Blunders (-3) B1 Any incorrect set of elements of P and R other than the misreading as below. e.g. { P \ (Q ∪ R )} = {4} . Misreadings (-1) M1 R \ P giving {1, 2, 3, 6}. Attempts (2 marks) A1 5 or 9 appear in the answer. Page 4 Part (b) (iii) 1(b) (iii) 5 marks Att 2 List the elements of: (P ∪ R ) ∩ Q Part (b) (iii) 5 marks (P ∪ R ) ∩ Q = {1, 2, 7, 8} Att 2 Blunders (-3) B1 Any incorrect set of elements of P and Q and R other than the misreading as below. B2 P ∪ R = {1,2,3,4,6,7,8} . Misreadings (-1) M1 (P ∩ R ) ∪ Q giving {1, 2, 5, 7, 8}. M2 (P ∪ R ) ∪ Q giving {1, 2, 3, 4, 5, 6, 7, 8}. M3 (P ∩ R ) ∩ Q giving {7}. Attempts (2 marks) A1 9 appears in the answer. Part (b) (iv) 1(b) (iv) List the elements of: (P ∪ Q ) Part (b) (iv) 5 marks Att 2 5 marks Att 2 / (P ∪ Q )/ = {3, 6, 9} Blunders (-3) B1 Any incorrect set of elements of P and Q other than the misreading as below. B2 (P ∪ Q ) = {1, 2, 4, 5, 7, 8} in this part. Misreadings (-1) / M1 (P ∩ Q ) giving {1, 2, 3, 4, 5, 6, 9,}. M2 P / ∪ Q / giving {1, 2, 3, 4, 5, 6, 9}. Attempts (2 marks) A1 Any incorrect listing of elements other than the misreadings above. Page 5 Part (c) 20(5,5,5,5)marks 1(c) In a class, all the students study Science (S) or Technical Graphics (T). A number of the students study both of these subjects. 22 students study Science. 12 students study Technical Graphics 8 study both subjects. Part (c) (i) 1(c) (i) 5 marks Att(2,2,2,2) Att 2 Represent this information in the Venn diagram below. S T Part (c) (i) 5 marks Att 2 S T 14 4 8 Blunders (-3) B1 Incorrect Venn diagram subject to S1 below. Slips (-1) S1 Numerical errors where work is clearly shown to a max of 3. Misreadings (-1) M1 Interchanges Technical Graphics and Science. Attempts (2 marks) A1 Any one correct relevant entry. A2 Incorrect work with numbers 8, 12, and 22. (work shown) Page 6 Part(c) (ii) 1(c) (ii) 5 marks How many students study Science only? Att 2 Part(c) (ii) * * * 5 marks Att 2 14 A correct answer written here in the space provided takes precedence over an incorrect Venn diagram. Accepts candidates work from previous part c (i). If no work appears here, award 2 marks if the correct answer appears in the Venn diagram. Blunders (-3) B1 Any incorrect use of the given numbers or the numbers from the candidates incorrect Venn diagram. {Subject to S1}. Slips (-1) S1 Numerical errors where work is clearly shown to a max of 3. Misreadings (-1) M1 Science read as Technical Graphics. Attempts (2 marks) A1 Incorrect work with numbers 8, and/or 22. ( work shown) Part(c) (iii) 1(c) (iii) 5 marks How many students are there in the class? Att 2 Part(c) (iii) * * 5 marks Att 2 26 A correct answer written here in the space provided takes precedence over an incorrect Venn diagram. Accepts candidates work from previous part c (i), c (ii). Note: Answer c (ii) + 12 added correctly merits full marks. Blunders (-3) B1 Any incorrect use of the given numbers or numbers from the candidates incorrect Venn diagram. {Subject to 2nd * above}. Slips (-1) S1 Numerical errors where work is clearly shown to a max of 3. S2 Written as 14 + 8 + 4. Attempts (2 marks) A1 Incorrect work with numbers 14, 8,4,12 or 22. Page 7 Part(c) (iv) 1(c) (iv) 5 marks How many students study only one of the two subjects? Part(c) (iv) Att 2 5 marks Att 2 18 * A correct answer written here in the space provided takes precedence over an incorrect Venn diagram. * Accepts candidates work from previous part c (i), c (ii) and c (iii). Note: Answer c (iii) - 8 merits full marks. Blunders (-3) B1 Any incorrect use of the given numbers or numbers from the candidates incorrect Venn diagram. {Subject to 2nd * above}. Slips (-1) S1 Numerical errors where work is clearly shown to a max of 3. S2 Written as 14 + 4. Attempts (2 marks) A1 Incorrect work with numbers 14, 8, 4, 12, or 22. Page 8 QUESTION 2 Part (a) Part (b) Part (c) 10 marks 20(5, 10, 5) marks 20(5, 5, 10) marks Att 3 Att 7(2, 3, 2) Att 7(2, 2, 3) Part (a) 10 marks 2(a) €6650 was shared between Ciarán and Sheila in the ratio 2:5. How much did each receive? Att 3 Part (a) Att 3 10 marks " 2 parts : 5 parts 6650 ⇒ = 950 7 Ciaran = 950 × 2 = €1900 Sheila = 950 × 5 = €4750 2+5=7 1 = 950 7 2 ⇒ = €1900 (C) 7 ⇒ 6650-1900 = €4750 (S) 2x :5x ⇒ 7 x = 6650 ⇒ x = 950 ⇒ 2 x = €1900 (C) ⇒ 5 x = €4750 (S) Blunders (-3) B1 B2 B3 B4 B5 B6 " Correct answer without work. Divisor ≠ 7 only and continues. Incorrect multiplier or fails to multiply. (each time). Error in transposition. Fails to find second amount. Adds instead of subtracts. e.g. 6650 + 1900 = 8550. Slips (-1) S1 Numerical errors to a max of 3. Misreadings (-1) M1 Interchanges Ciaran and Sheila. Attempts (3 marks) A1 A2 A3 A4 6650 6650 and/or and stops. 2 5 2 5 Indicates 7 parts or 2 parts or 5 parts or or or 2+5=7 and stops. 7 7 Indicates multiplication of 6500 by 2 and/or 5 and stops. Both answers added together equal €6650. (No work shown). Divisor ≠ 7 e.g. Worthless (0) W1 Incorrect answer without work. {Subject to A4}. Page 9 Part (b) (i) 5 marks 2(b) (i) Simplify a 8 × a 10 , giving your answer in the form, a n where n ∈ N. 5 7 a ×a Part (b) (i) 5 marks " a ×a a = 12 = a 6 5 7 a ×a a 8 10 Att 2 18 ⎛ a8 ⎜⎜ 5 ⎝a ⎞ ⎛ a 10 ⎟⎟ × ⎜⎜ 7 ⎠ ⎝a Att 2 ⎞ 3 ⎟⎟ = a × a 3 = a 6 ⎠ a a a × ……. ……. = a 6 a a a Blunders (-3) B1 Correct answer without work. B2 Error in calculation involving indices. B3 Error in number of a’s in the extended form. B4 Error in elimination in the extended form. B5 Fails to finish. " Slips (-1) a 18 S1 =6 a 12 S2 Answer left a × a × a × a × a × a . Attempts (2 marks) A1 Some correct manipulation of indices. e,g, 8+10, Worthless (0) W1 Incorrect answer without work. Page 10 18 3 5 , a , a , or a and stops. 12 Part (b) (ii) 2(b) (ii) 10 marks Att 3 By rounding each of these numbers to the nearest whole number, 24 ⋅ 092 estimate the value of . 6 ⋅ 1 − 2 ⋅ 93 Part (b) (ii) 10 marks " 6 24⋅1 −⋅ 092 2 ⋅ 93 Att 3 is approximately equal to 24 6 _ 24 = 3 = 8 3 24 and stops ⇒ 4 marks. 6−3 * No penalty if the intermediate step between approximations and final answer is not shown. 24 not shown. i.e 3 24 ⋅ 092 * Special Case: = 7 ⋅ 6 presented in this part ⇒ Attempt 3 marks. 6 ⋅ 1 − 2 ⋅ 93 Blunders (-3) B1 Correct answer without work. B2 Error(s) in rounding off to the nearest whole number. B3 Decimal error in calculation of final value. B4 An arithmetic operation other than indicated. 24 24 − or similar. B5 Error(s) in the manipulation of the denominator. e.g. 6 3 * " Slips (-1) S1 Numerical errors to a max of 3. Attempts (3 marks) A1 Only one or two approximations made to the given numbers and stops. A2 No rounding off applied to given numbers. Worthless (0) W1 Incorrect answer without work. Page 11 Part (b) (iii) 2(b)(iii) Part (b) (iii) 5 marks Using a calculator, or otherwise, find the exact value of Att 2 24 ⋅ 092 . 6 ⋅ 1 − 2 ⋅ 93 5 marks 24 ⋅ 092 24 ⋅ 092 = =7 ⋅6 6 ⋅ 1 − 2 ⋅ 93 3 ⋅ 17 Blunders (-3) B1 Decimal error. 24 ⋅ 092 B2 Treats as − 2.93 = 3 ⋅ 949508197 − 2 ⋅ 93 =1 ⋅ 019 ….{B1 may occur}. 6 ⋅1 24 ⋅ 092 B3 Treats as 24 ⋅ 092 − = 24 ⋅ 092 − 8 ⋅ 2225 = 15 ⋅ 8695. . {B1 may occur}. 2 ⋅ 93 24 ⋅ 092 24 ⋅ 092 B4 Treats as = = 2 ⋅ 66799 . {B1 may occur}. 6 ⋅ 1 + 2 ⋅ 93 9 ⋅ 03 24 ⋅ 092 24 ⋅ 092 B5 Treats as = = 1 ⋅ 347955016 . {B1 may occur}. 6 ⋅ 1 × 2 ⋅ 93 17 ⋅ 873 24 ⋅ 092 B6 Treats as 24 ⋅ 092 − = 24 ⋅ 092 − 7 ⋅ 6 = 16 ⋅ 492. {B1 may occur}. 3 ⋅ 17 24 ⋅ 092 24 ⋅ 092 B7 Treats as − = 3 ⋅ 9495 − 8 ⋅ 2225.... = − 4 ⋅ 2755 . {B1 may occur}. 6 ⋅1 2 ⋅ 93 Slips (-1) S1 Numerical errors to a max of 3. S2 Any rounding off. Attempts (2 marks) A1 Any correct relevant calculation and stops. Worthless (0) W1 Incorrect answer without work. Page 12 Att 2 Part(c) (i) 2(c) (i) 5 marks Att 2 1 2 Using a calculator, or otherwise, find the exact value of (2 ⋅ 25) . Part(c) (i) 5 marks 1 2 (2 ⋅ 25) = Att 2 3 =1·5 2 Blunders (-3) 1 B1 B2 Mishandles (2 ⋅ 25) 2 e.g. (2 ⋅ 25) = 5 ⋅ 0625 . Decimal error. 2 Attempts (2 marks) A1 2 ⋅ 25 and stops. 1 A2 2 ⋅ 25 × = 1 ⋅ 125 . 2 Worthless(0) W1 2 ⋅ 25 × 2 or 2 ⋅ 75 . Part(c) (ii) 2(c) (ii) 5 marks Att 2 Using a calculator, or otherwise, multiply 54·5 by 60 and express your answer in the form a × 10 n , where 1 ≤ a < 10 and n ∈ N Part(c) (ii) " 5 marks 54 ⋅ 5 × 60 = 3270 = 3 ⋅ 27 ×10 3 Blunders (-3) B1 B2 Correct answer without work. Decimal error. " Slips (-1) S1 Numerical errors to a max of 3. S2 Rounds off to, 3 ⋅ 3×10 3 or 3 ⋅ 0 ×10 3 S3 Incorrectly rounds off. e.g. 3 ⋅ 2 ×10 3 also attracts S2. S4 Incorrect format, where a < 1 or a ≥ 10 and n ∉ N. Attempts (2 marks) A1 Any relevant step. e.g. Partial multiplication. Page 13 Att 2 Part(c) (iii) 2(c) (iii) 10 marks Using a calculator, or otherwise, evaluate (6 ⋅ 9) 2 − 139 ⋅ 8 ÷ 3 ⋅ 55. Give your answer correct to two decimal places Part(c) (iii) " * 10 marks Att 3 Att 3 = 47 ⋅ 61 − 11 ⋅ 823705 ÷ 3 ⋅ 55 = 47 ⋅ 61 − 3 ⋅ 330621127 = 44 ⋅ 27937887 = 44 ⋅ 28 Correct answer (without work) incorrectly rounded off ⇒ 6 marks Blunders (-3) " B1 B2 Correct answer without work. Mishandles (6 ⋅ 9) 2 . B3 B4 B5 B6 B7 B8 B9 Mishandles 139 ⋅ 8 . Error in 11 ⋅ 823705 ÷ 3 ⋅ 55 or candidate's equivalent from previous work. Error in 47 ⋅ 61 − 3 ⋅ 330621127 or candidate's equivalent from previous work. Decimal error. Subtracts before Division 35 ⋅ 786295 ÷ 3 ⋅ 55 = 10 ⋅ 08064648 = 10 ⋅ 08 {Note S2,S3 } Use of mathematical operator other than that which is indicated. Works as 47 ⋅ 61 ÷ 3 ⋅ 55 − 11 ⋅ 823705 = 1 ⋅ 587562606 = 1 ⋅ 59 .{Note S2,S3 } Slips (-1) S1 Numerical errors to a max of 3. S2 Each premature rounding off that effects the final answer to a max of 3. S3 Fails to round off or rounds off incorrectly when giving final answer. Attempts (3 marks.) A1 Any correct relevant step e.g. (6 ⋅ 9) 2 = 47 ⋅ 61 , 139 ⋅ 8 = 11 ⋅ 823705 . Page 14 QUESTION 3 Part (a) Part (b) Part (c) 10 marks 20(10, 10) marks 20(10, 10) marks Att 3 Att 6(3, 3) Att 6(3, 3) Part(a) 10 marks 3(a) In one week Bríd sent 26 text messages on her mobile phone 11 of these messages cost 8c each The rest of the text messages cost 12c each. Find the total cost of Bríd’s texting. Att 3 Part (a) Att 3 10 marks " 26 – 11 = 15 11 × 8 = 88 15 × 12 = 180 Total Cost = 268 c (€ 2 ⋅ 68 ) * * * 26 – 11 = 15 8 + 8 …..11 Times = 88 12 + 12 ….15 Times = 180. Total Cost = 268 c (€ 2 ⋅ 68 ) No penalty for omission of € symbol. Accept 268c, (€ 2 ⋅ 68 ) Adds 8 + 12 = 20 and stops merits 3 marks (Oversimplification). Blunders (-3) B1 B2 B3 B4 B5 B6 B7 Correct answer without work. " Fails to subtract 11 from 26. Each missing product when finding each cost e.g. 11 not multiplied by 8. Each missing item when finding total cost e.g. Expensive texts omitted. Fails to find total cost i.e. no addition. Operation other than addition when finding total cost. Decimal error e.g. € 26 ⋅ 8 (Note: 1st* above). Slips (-1) S1 Numerical errors to a max of 3. Misreadings (-1) M1 15 texts @ 8c and 11 texts @ 12c. Attempts (3 marks) A1 Any attempt at addition /multiplication. Worthless (0) W1 Incorrect answer without work. Page 15 Part (b) (i) 3(b) (i) 10 marks John’s gross pay is €23 000. His tax credit is €3400 He pays income tax at the rate of 20% Find John’s take-home pay. Part (b) (i) 10 marks " Gross Pay Tax @ 20% Tax Credit Tax-Due Take-home Pay €23 000 €4600 €3400 €1200 €21,800 20 = 4600 100 or 23,000 × 0.2 = 4600 Tax Due = 4600 – 3400 = 1200 Take-home Pay = 23000 - 1200 Tax = 23,000 × = €21,800 Blunders (-3) B1 B2 B3 B4 B5 B6 Correct answer without work. " Mishandles 20% of 23,000. {Must use 23 000} Decimal error. Misuse of Tax Credit Incorrect use of Tax Amount. Fails to finish. {B4 may apply} Slips (-1) S1 Numerical errors to a max of 3 Attempts (3 marks) 20 A1 Some use of 100 in attempt to find percentage e.g. 20% = 100 and stops. Worthless (0) W1 Incorrect answer without work Page 16 Att 3 Att 3 Part (b) (ii) 3(b) (ii) 10 marks VAT at 21% is added to a bill of €255 Calculate the total bill. Part (b) (ii) Att3 10 marks Att3 " 100 % = 255 255 100 255 121 % = × 121 100 = 2 ⋅ 55 121 1% = Total Bill = € 308 ⋅ 55 * 21 100 21 VAT = × 255 100 = 53.55 21 % = 255 ×1 ⋅ 21 Total Bill = € 308 ⋅ 55 Total Bill = 255 + 53 ⋅ 55 Total Bill = € 308 ⋅ 55 € 53⋅ 55 without work and stops merits 4 marks. Blunders (-3) B1 B2 B3 B4 B5 B6 B7 Correct answer without work. " Decimal error 121 21 or and continues (giving answers 210 ⋅ 74 or 1214 ⋅ 29 ). Inverts 100 100 Mishandles 21%. e.g.255 × 21 or 255 ÷ 21. Note: {255 must be used}. 255 taken as 121%. No addition of VAT (as per candidates work) to the bill. Subtraction of VAT ( as per candidates work) from the bill. Slips (-1) S1 Numerical errors to a max of 3. Misreadings (-1) M1 Reads as €225. Attempts (3 marks) 21 and stops. A1 100 A2 100% = 255 and stops. 255 A3 and stops. 100 21 A4 100 × and stops. 255 255 and stops. A5 21 A6 Use of any other %. A7 255 + 21% and stops. Page 17 Part(c) (i) 3(c) (i) 10 marks €15 000 is invested at 3% per annum What is the amount of the investment at the end of the first year? Part(c) (i) 10 marks Att 3 Att 3 " 15000 100 15000 3%= ×3 100 Interest = 450 1%= P×R 100 15000 × 3 I = 100 I = 450 I = Amount = 15000 + 450 Amount = 15000 + 450 Amount = €15 450 Amount = €15 450 * Amount =15000 × 1 ⋅ 03 Amount = €15 450 €450 (without work) and stops ⇒ 4 marks. Blunders (-3) B1 B2 B3 B4 B5 B6 B7 Correct answer without work. " 15000 × 100 Mishandles 3 %. e.g. Note:{15000 must be used}. 3 Decimal error (once only). Stops at interest i.e. fails to calculate amount. Subtracts to calculate amount. 15000 × 3 Mathematical error(s) working with . 100 1 ⋅ 03 treated as 1 ⋅ 3 . Slips (-1) S1 Numerical errors to a max of 3. Attempts (3 marks) A1 Correct formula with or without substitution and stops. A2 Some use of 100 in attempt to find percentage e.g. 3 % = A3 15000 + 3% and stops. Worthless (0) W1 Incorrect answer without work. Page 18 3 or 1 ⋅ 03 and stops. 100 Part(c) (ii) 3(c) (ii) 10 marks Att 3 €1450 is withdrawn from this amount at the beginning of the second year. The interest rate for the second year is 3·5%. What is the amount of the investment at the end of that year? Part(c) (ii) 10 marks Att 3 " Principal for second year = 15450 - 1450 = 14000 Amount =14000 × 1 ⋅ 035 P×R 14000 1% = I = 100 100 Amount = €14 490 14000 × 3 ⋅ 5 14000 3.5 % = × 3⋅5 I = 100 100 Interest = 490 I = 490 Amount = 14000 + 490 Amount = 14000 + 490 Amount = €14 490 Amount = €14 490 * * * * No penalty for consistent error(s) already penalised in (c) (i). Accept candidates work from previous part (c) (i). €490 (without work) and stops ⇒ 4 marks. €14000 (without work) and stops ⇒ 3 marks. Blunders (-3) B1 B2 B3 B4 B5 B6 B7 B8 B9 Correct answer without work. " Incorrect principal for second year. Incorrect interest rate for second year. 14000 × 100 Mishandles 3.5 %. e.g. see (1st * above) 3.5 Decimal error (once only). Stops at interest i.e. fails to calculate amount. Subtracts to calculate amount. 14000 × 3 ⋅ 5 Mathematical error(s) working with 100 1 ⋅ 035 treated as 1 ⋅ 35 Note:{14000 must be used}. Slips (-1) S1 Numerical errors to a max of 3. Attempts (3 marks) A1 Correct formula with or without substitution and stops. A2 Some use of 100 in attempt to find percentage e.g. 3 ⋅ 5 % = A3 14000 + 3·5% and stops. Worthless (0) W1 Incorrect answer without work. Page 19 3⋅5 or 1 ⋅ 035 and stops. 100 QUESTION 4 Part (a) Part (b) Part (c) Part(a)(i) 4(a)(i) 15(10, 5) marks 15(10, 5) marks 20(10, 10) marks 10 marks If x = 3 , find the value of : (i) Part(a)(i) " * Att 3 4x + 5 10 marks 4x + 5 = 4(3) + 5 = 12 + 5 = 17 12 + 5 ⇒ 9 marks. Blunders (-3) B1 B2 B3 B4 B5 B6 Correct answer without work. " Leaves 4(3) in the answer. Incorrect substitution and continues Combines “x's”to “numbers” and continues. e.g. 4 x + 5 = 9 x = 9(3) = 27 . Breaks order i.e. [ 4(3 + 5) = 32 ]. Treats 4(3) as 7 or 43 or similar. Slips (-1) S1 Numerical errors to a max of 3. Attempts (3 marks) A1 Substitutes for x and stops e.g. 4(3) A2 Any correct step. Worthless (0) W1 Combines “x's”to “numbers” and stops. Page 20 Att 5(3, 2) Att 5(3, 2) Att 6(3, 3) Att 3 Part (a) (ii) 4(a) (ii) 5 marks If x = 3 , find the value of : (ii) Part (a) (ii) 2 x 2 − 11 5 marks " * Att 2 2 x 2 − 11 = 2(3) − 11 = 2(9) - 11 = 18 - 11 = 7 2 18 - 11 ⇒ 4 marks. Blunders (-3) B1 B2 B3 B4 B5 B6 B7 B8 B9 Correct answer without work. Leaves 2(9) in the answer. 2 2 Mishandles (3) e.g. (3) = 6. " Mishandles 2(3) e.g 2(3) = (6) . Mathematical error. e.g. 18 - 11 = - 7. Incorrect substitution and continues. Combines “x's ”to “numbers” and continues. e.g. 2 x 2 − 11x = − 9 x 2 Breaks order i.e. [ 2(9 − 11) = − 4 ]. Treats 2(9) as 11 or 29 or similar. 2 2 2 Slips (-1) S1 Numerical errors to a max of 3. . Attempts (2 marks) 2 A1 Substitutes for x and stops e.g. 2(3) A2 Any correct step. Worthless (0) W1 Combines “ x 2 ” to “numbers” and stops. Page 21 Att 2 Part (b) (i) 4(b) (i) Part (b) (i) " 10 marks Solve the equation 4(5 x + 6) = 84 . 4(5 x + 6 ) = 84 20 x + 24 = 84 20 x 20 x x 10 marks = 84 − 24 = 60 =3 Att 3 4(5 x + 6 ) = 84 84 5x + 6 = 4 5x + 6 = 21 5x = 21 − 6 5x = 15 =3 x Blunders (-3) B1 B2 B3 B4 B5 Correct answer without work. " e.g. x = 3 stated or substituted. Error in distributive law and continues,e.g. 20 x + 6 = 84 (once only). Error in transposition. (each time). Combines “x's”to “numbers” and continues. e.g.. 20 x + 24 = 44 x Stops at 20 x = 60 or similar. Slips (-1) S1 Numerical errors to a max of 3. 60 or similar. S2 Leaves as 20 Attempts (3 marks) A1 Any correct step. A2 Particular case verified for any value of x other than 3. Worthless (0) W1 Combines “x's” to “numbers” and stops. Page 22 Att 3 Part (b) (ii) 4(b) (ii) 5 marks Write in its simplest form 3 x 2 − 2 x + 6 − x(2 x − 3) Part (b) (ii) 5 marks 3x − 2 x + 6 − x(2 x − 3) 2 " 3x 2 − 2 x + 6 − 2 x 2 + 3x x2 + x + 6 Blunders (-3) B1 B2 B3 B4 B5 Correct answer without work. " Error(s) in distribution. Combining unlike terms. Fails to group or groups incorrectly. Treats as 3x 2 − 2 x + 6 − x (2 x − 3) and continues. ( ) Slips (-1) S1 Numerical errors to a max of 3. Attempts (2 marks) A1 Any correct multiplication.e.g. 3 x A2 Any correct grouping of terms. A3 A correct step. A4 Substitutes a value of “ x ” and continues. Worthless (0) W1 Combining unlike terms and stops. W2 No attempt at distribution but A2 may apply to subsequent work. Page 23 Att 2 Att 2 Part(c) (i) 10 marks 4(c) (i) Liam drove from Town A to Town B, a distance of x km. He then drove from Town B to Town C, a distance of (2x + 1) km. The total distance that he drove was 56 km. Find the value of x, correct to the nearest kilometre. Att3 Part(c) (i) Att3 10 marks x + 2 x + 1 = 56 3x + 1 = 56 = 56 − 1 3x = 55 3x " x x 1 55 or 18 ⋅ 33333 or 18 3 3 = 18 = Blunders (-3) B1 B2 B3 B4 B5 B6 Correct answer without work. " Error(s) in forming equation for distance travelled. Error in grouping terms. e.g. 2 x + 1 = 56 and continues.(once only). Error in transposition.(each time). Combines “x's”to “numbers”. e.g. 4 x = 56 and continues. Stops at 3x = 55 or candidate's equivalent. {S2 also applies} Slips (-1) S1 Numerical errors to a max of 3. 1 55 S2 Leaves as or 18 ⋅ 333 or 18 or candidate's equivalent. 3 3 Attempts (3 marks) A1 Any correct step. A2 Illustrates information on a diagram and stops. Worthless (0) W1 Combines “x's” to “numbers” and stops. W2 Incorrect answer no work e.g. x = 56 . Page 24 Part(c) (ii) 4(c) (ii) Solve for x and for y: 10 marks Att3 3x + 5 y = 13 x + 2y = 5 . Part(c) (ii) " 10 marks I II 3 x + 5 y = 13 x + 2y = 5 3 x + 5 y = 13 x + 2y = 5 6 x + 10 y = 26 − 5 x − 10 y = − 25 x = 1 ⇒ y=2 * * Att3 or 3 x + 5 y = 13 − 3x − 6 y = − 15 or − y = −2 y = 2 ⇒ x =1 x = 5 − 2y 3(5 − 2 y ) + 5 y = 13 15 − 6 y + 5 y = 13 −y = −2 y =2 ⇒ x =1 Apply only one blunder deduction (B2 or B3) to any error(s) in establishing the first equation in terms of x only or the first equation in terms of y only. Finding the second variable is subject to a maximum deduction of (3). Blunders (-3) B1 B2 Correct answers without work. " e.g. x =1, y = 2. stated or substituted. Error(s) in establishing the first equation in terms of x only [ x = 1 ] or the first equation in terms of y only [ − y = − 2 ] through elimination by cancellation. B3 Error(s) in establishing the first equation in terms of x only [ x = 5 − 2 y ] or the first equation in terms of y only [ 5 y = 13 − 3x ] through elimination by substitution. B4 B5 B6 B7 Errors in transposition in solving the first one variable equation. Errors in transposition when finding the second variable. Incorrect substitution when finding second variable. Finds one variable only. Slips (-1) S1 Numerical errors to a max of 3 Attempts (3 marks) A1 Attempt at transposition and stops. A2 Multiplies either equation by some number and stops. Page 25 QUESTION 5 Part (a) Part (b) Part (c) 10 marks 20(5, 5, 5, 5) marks 20(5, 5, 10) marks Part (a) 10 marks 5(a) Att 3 Find the values of x for which 3x + 2 < 11, x ∈ N Part (a) " 10 marks 3x + 2 < 11 3x < 11 − 2 3x < 9 x <3 { 0, 1, 2} Blunders (-3) B1 B2 B3 B4 B5 B6 B7 Att 3 Att 8(2, 2, 2, 2) Att 7(2, 2, 3) Correct answer without work. " Error in transposition. (each time). Combining unlike terms. Mishandles the direction of inequality e.g. 3 x > 9 Treats inequality as equality and continues. {S3 may apply} Combines “x's” to “numbers”. e.g.. 5 x < 11 and continues. x < 3 and stops. Slips (-1) S1 Numerical errors to a max of 3. S2 < taken as ≤ . S3 No listing or incorrect listing of values. {Subject to max penalty of 3}. Misreadings (-1) M1 3x + 2 < 1 , and continues. Attempts (3 marks) A1 Attempt at transposition and stops. A2 Particular case verified. Page 26 Att 3 Part (b) (i) 5(b) (i) Factorise: Part (b) (i) 5 marks 16 xy + 11 y Att 2 5 marks y (16 x + 11) Att 2 Blunders (-3) B1 An incorrect factor B2 Removes factor incorrectly. Attempts (2 marks) A1 Indication of common factor. e.g. underline y 's and stops. Part (b) (ii) 5(b) (ii) Factorise: Part (b) (ii) " * 5 marks 5 x + 10 y + ax + 2ay Att 2 5 marks 5 x + 10 y + ax + 2ay Att 2 5 x + 10 y + ax + 2ay or x(5 + a ) + 2 y (5 + a ) 5( x + 2 y ) + a ( x + 2 y ) (5 + a )(x + 2 y ) (x + 2 y )(5 + a ) Accept also (with or without brackets) for 5 marks any of the following (5 + a ) and (x + 2 y ) {The word and is written down.} (5 + a ) or (x + 2 y ) {The word or is written down.} (5 + a ) , (x + 2 y ) {A comma is used} Blunders (-3) B1 B2 B3 B4 Correct answer without work. " Stops after first line of correct factorisation. e.g. . 5( x + 2 y ) + a (x + 2 y ) or equivalent. Error(s) in factorising any pair of terms. Incorrect common factor and continues. e.g. 2(ay + 5 y ) + x(a + 5) Slips (-1) S1 (5 + a ) ± ( x + 2 y ) S2 Correct first line of factorisation but ends as 5a ( x + 2 y ) . Attempts (2 marks) A1 Pairing off, or indication of common factors and stops. A2 Correctly factorises any pair and stops. Page 27 Part (b) (iii) 5(b) (iii) 5 marks Att 2 x − x − 90 2 Factorise: Part (b) (iii) 5 marks Att 2 x 2 − x − 90 x x 2 + 9 x − 10 x − 90 x( x + 9 ) − 10( x + 9 ) (x − 10)(x + 9) +9 x −10 ⇒ ( x − 10 )( x + 9 ) * − (− 1) ± (− 1)2 − 4(1)(− 90) 2(1) 1 ± 19 1 ± 1 + 360 = 2 2 − 18 20 = 10 =−9 2 2 ⇒ ( x − 10 )( x + 9) Accept also (with or without brackets) for 5 marks any of the following (x − 10) and (x + 9) {The word and is written down.} (x − 10) or (x + 9) {The word or is written down.} (x − 10) , (x + 9) {A comma is used} Incorrect two term linear factors of. x 2 − x − 90 formed from correct (but inapplicable) factors of x 2 and − 90 .e.g (x − 45)( x + 2 ) . B2 Incorrect factors of x 2 . B3 Incorrect factors of − 90 . B4 Correct cross method but factors not shown and stops. B5 x( x + 9) − 10( x + 9 ) or similar and stops. B6 Incorrect common factor and continues. B7 Incorrect quadratic formula and continues. B8 Error in quadratic formula. (each time). B9 Answer left as roots. B10 Sign error(s) in substituted formula. B11 Error in square root or square root ignored. B1 Slips (-1) S1 Numerical errors to a max of 3. S2 Uses quadratic equation formula, but has wrong sign in factors. Attempts (2 marks) A1 Correct quadratic equation formula quoted and stops A2 Correct factors of either x 2 or ± 90. A3 Any correct step. Worthless (0 marks) W1 x 2 − x = 90 or similar and stops. W2 Combines “x's”to “numbers” and continues or stops. Page 28 Part (b) (iv) 5 marks 5(b) (iv) Factorise: Att 2 x 2 − 121 Part (b) (iv) * * * 5 marks (x − 11)(x + 11) Accept also (with or without brackets) for 5 marks any of the following (x − 11) and (x + 11) {The word and is written down.} (x − 11) or (x + 11) {The word or is written down.} (x − 11) , (x + 11) {A comma is used} Quadratic equation formula method is subject to slips and blunders. x − 121 x + 121 merits 5 marks. ( )( Att 2 ) Blunders (-3) B1 Incorrect two term linear factors of x 2 − 121 formed from correct (but inapplicable) factors of x 2 and − 121 .e.g (x − 121)(x + 1) . B2 Incorrect factors of x 2 . B3 Incorrect factors of −121 . B4 (11 − x )(11 + x ) . B5 (x − 121)(x + 121) . B6 Answer left as roots. Slips (-1) S1 (x − 11) ± (x + 11) Attempts (2 marks) A1 Correct factors of x 2 only. A2 Correct factors of ± 121 only. A3 x or ± 11 appears. A4 x 2 − 121 = x.x − 11.11 and stops. A5 A6 A7 Mention of the difference of two squares .e.g. { x 2 − (121) } Correct quadratic equation formula quoted and stops. 121 2 Worthless (0 marks) W1 Combines “x's” to “numbers” and continues or stops. Page 29 Part(c) (i) 5(c)(i) 5 marks Att2 2x − 1 x+7 + as a single fraction. 5 2 Give your answer in its simplest form. Express Part(c) (i) " 5 marks 2x − 1 x+7 + 5 2 2(2 x − 1) + 5( x + 7 ) 10 4 x − 2 + 5 x + 35 10 9 x + 33 10 Att2 2x − 1 3x + 6 x + 7 Zero marks. + = 5 2 7 Blunders (-3) * B1 B2 B3 B4 Correct answer without work. " Error(s) in distribution. e.g 2(2 x − 1) = 4 x − 1 . Mathematical error e.g. -2 +35 = -33. 2(-1) = 2. Incorrect common denominator and continues. B5 Incorrect numerator from candidate's denominator e.g. B6 B7 No simplification of numerator. Omitting denominator. Slips (-1) S1 Drops denominator. S2 Numerical error to a max of 3. S3 Answer not in simplest form. e.g. 18 x + 66 . 20 Attempts (2 marks) A1 10 only or a multiple of 10 only appears. A2 Any correct step. Worthless (0) x 8x W1 + , or 5 2 ⎛ 2 x − 1 ⎞⎛ x + 7 ⎞ ⎟ and stops. ⎟⎜ ⎜ ⎝ 5 ⎠⎝ 2 ⎠ Page 30 5(2 x − 1) + 2( x + 7 ) . 10 Part(c) (ii) 5(c) (ii) 5 marks Hence, or otherwise, solve the equation Part(c) (ii) * 2x − 1 x + 7 + = 6. 5 2 5 marks 9 x + 33 10 9 x + 33 9x 9x " Att2 = 6 = 60 = 60 − 33 = 27 = 3 x Accept candidates answer from previous work. Blunders (-3) B1 B2 Correct answer without work. " Error in transposition. (each time) Slips (-1) S1 Numerical error to a max of 3. 27 . S2 Leaves as 9 Attempts (2 marks) A1 Answer from (c) (i) written in this part or worked again in this part. A2 Any correct step and stops. A3 Particular case verified. Page 31 Att2 Part(c) (iii) 10 marks 5(c) (iii) Solve the equation: Att3 x 2 + 5 x − 36 = 0. Part(c) (iii) 10 marks Att3 " − (5) ± x 2 + 5 x − 36 = 0 x 2 + 9 x − 4 x − 36 = 0 x( x + 9 ) − 4( x + 9 ) = 0 x +9 ⇒ x=−9 x −4 (x + 9)(x − 4) = 0 x =4 (5)2 − 4(1)(− 36) 2(1) − 5 ± 25 + 144 − 5 ± 169 − 5 ± 13 = = 2 2 2 8 − 18 =4 =−9 2 2 (x + 9)(x − 4) ⇒ x =−9 x =4 Blunders (-3) B1 B2 Correct answers without work. " e.g. x = 4, x = − 9 stated or substituted. Incorrect two term linear factors of x 2 + 5 x − 36 formed from correct (but inapplicable) factors of x 2 and − 36 . e.g. (x − 12 )( x + 3) B3 B4 B5 B6 B7 B8 B9 B10 Incorrect factors of x 2 . Incorrect factors of − 36 . Correct cross method and factors not shown and stops.{B8 also applies} x( x + 9) − 4( x + 9 ) or similar and stops. {Note: B8 also applies }. Incorrect root(s) from factors. No roots given. One root only Error in quadratic formula. (each time). Slips (-1) S1 Numerical errors to a max of 3. p S2 Leaves as . q Attempts (3 marks) A1 Correct factors of x 2 only A2 Correct factors of ± 36 only. A3 Some effort at factorisation. A4 Correct quadratic equation formula quoted and stops A5 Any correct step. Worthless (0) W1 Combines unlike terms and continues or stops. Page 32 QUESTION 6 Part (a) Part (b) Part (c) Part(a) 6(a) 10(5, 5) marks 25(15, 10) marks 15(5, 5, 5) marks 10(5,5) marks P = {(1,3) (4,6) (5,8) (7,9)} Write out the domain and range of P. Part(a) Domain Att 4(2, 2) Att 8(5, 3) Att 6(2, 2, 2) Att 4(2,2) 5 marks Domain = Att 2 {1, 4, 5, 7} Slips (-1) S1 Each correct element omitted and/or each incorrect element included. {See M1} Misreadings (-1) M1 Correct range. i.e. { 3,6,8,9}given. Attempts (2 marks) A1 One element of domain. A2 Domain { 1 → 7 } Worthless (0) W1 No element of the domain appears. {See M1} Part(a) Range 5 marks Range = {3, 6, 8, 9} Slips (-1) S1 Each correct element omitted and/or each incorrect element included. {See M1} Misreadings (-1) M1 Correct domain. i.e. {1, 4, 5, 7} given. Attempts (2 marks) A1 One element of range. A2 Range{ 3 → 9 } Worthless (0) W1 No element of the range appears. {See M1} Page 33 Att 2 Part (b) 6(b) 25(15, 10) marks Draw the graph of the function f : x → 2 + 3x − x 2 in the domain −1 ≤ x ≤ 4, where x ∈ R Part (b) Table Att 8(5, 3) 15 marks Att 5 " f ( −1) = 2 + 3 ( −1) − ( −1) = -2 x -1 0 1 2 3 4 f (0) = 2 + 3 (0) − (0) = 2 2 2 2 2 2 2 2 f (1) = 2 + 3 (1) − (1) 2 = 4 +3x -3 0 3 6 9 12 f ( 2) = 2 + 3 ( 2) − ( 2) = 4 −x 2 -1 0 -1 -4 -9 -16 f ( 3) = 2 + 3 ( 3) − ( 3) = 2 f (x ) -2 2 4 4 2 -2 f ( 4) = 2 + 3 ( 4) − ( 4) 2 * 2 2 2 2 = -2 Error(s) in each row /column attract a maximum deduction of 3. Blunders (-3) B1 Treats − x 2 taken as x 2 and places '' x 2 '' in the table or function.. B2 − x 2 taken as −2x all the way. [In row headed − x 2 by candidate] B3 + 3x taken as + 3 all the way. [In row headed + 3x by candidate] B4 2 calculated as 2 x all the way.[In row headed 2 by candidate] B5 Adds in top row when evaluating f (x) . B6 Omits “2” row or omits “3 x ” row. B7 Omits a value in the domain (each time). B8 Each incorrect image without work. Slips (-1) S1 Numerical errors to a max of 3 in any row / column. Misreadings (-1) M1 Misreads “ + 3x ” as “-3 x ” and places “-3 x ” in the table or function M2 Misreads “2”as “-2” and places “-2” in the table or function. Attempts (5 marks) A1 Omits − x 2 row from table or treats − x 2 as ±x. A2 Any effort at calculating point(s). A3 Only one point calculated and stops. Page 34 Part (b) Graph 10 marks Att 3 " 5 4 3 2 1 0 -2 -1 0 1 2 3 4 5 -1 -2 -3 * * * * Accept candidate's values from previous work. Only one correct point graphed correctly ⇒ Att 5 + Att 3 Correct graph but no table ⇒ full marks i.e. (15+10) marks. Accept reversed co-ordinates if (i) if axes not labelled or (ii) if axes are reversed to compensate (see B1 below) Blunders (-3) B1 Reversed co-ordinates plotted against non-reversed axes (once only) {See 4th * above}. B2 Scale error (once only). B3 Points not joined or joined in incorrect order (once only). Slips (-1) S1 Each point of candidate graphed incorrectly. {Tolerance ± 0.25 } S2 Each point from table not graphed [See 2nd * above]. Attempts (3 marks) A1 Graduated axes (need not be labelled). Page 35 Part(c) (i) 6(c) (i) 5 marks Given that y = x + 1, complete the table below Part(c) (i) * 5 marks Att 2 x 0 1 2 3 y 1 2 3 4 Accept candidate's values without work. Slips(-1) S1 Each y value omitted or incorrect. Attempts(2marks) A1 Any one correct value of y . A2 Any effort at calculating point where work is shown. Page 36 Att 2 Part(c) (ii) 6(c) (ii) 5 marks Att 2 On the grid below, the graph of the line y = 3 − x is drawn. Using your answers from (i), draw the graph of y = x + 1 on the same grid Part(c) (ii) Graph 5 marks Att 2 4 y =3−x 3 2 1 0 -2 -1 0 1 2 3 4 -1 -2 * * Accept candidate's values from previous work. Only one point listed and graphed correctly ⇒ Att 2 + Att 2 Blunders (-3) B1 Reversed co-ordinates ( y , x ) plotted. B2 Points not joined or joined in incorrect order. Slips (-1) S1 Each point of candidate graphed incorrectly. {See B1} S2 Each point from table not graphed or not contained on the candidate’s graph. Attempts (2 marks) A1 Any straight line drawn. Page 37 5 Part(c)(iii) Intersection 5 marks 6(c)(iii) Use the graphs drawn in 6 (c) (ii) to write down the coordinates of the point of intersection of the two lines y = 3 − x and y = x + 1 . Att2 Part(c)(iii) Intersection Att2 " 5 marks Point of intersection = (1,2) * Accept previous graph from c (ii). Blunders(-3) B1 Answer not presented in designated box. B2 Answer beyond tolerance. {Tolerance ± 0.25 }. Attempts(2marks) A1 Indicates correctly either x or y co-ordinate of point of intersection. A2 Point of intersection indicated. A3 Algebraic evaluation. Worthless(0) W1 Answers outside of tolerance without graphical indication. Page 38 Coimisiún na Scrúduithe Stáit State Examinations Commission JUNIOR CERTIFICATE EXAMINATION 2006 MATHEMATICS - ORDINARY LEVEL - PAPER 1 1. GENERAL GUIDELINES FOR EXAMINERS Penalties of three types are applied to candidates’ work as follows: • Blunders - mathematical errors/omissions (-3) • Slips- numerical errors (-1) • Misreadings (provided task is not oversimplified) (-1). Frequently occurring errors to which these penalties must be applied are listed in the scheme. They are labelled: B1, B2, B3,…, S1, S2,…, M1, M2,…etc. These lists are not exhaustive. 2. When awarding attempt marks, e.g. Att(3), note that • any correct, relevant step in a part of a question merits at least the attempt mark for that part • if deductions result in a mark which is lower than the attempt mark, then the attempt mark must be awarded • a mark between zero and the attempt mark is never awarded. 3. Worthless work is awarded zero marks. Some examples of such work are listed in the scheme and they are labelled as W1, W2,…etc. 4. The phrase “hit or miss” means that partial marks are not awarded – the candidate receives all of the relevant marks or none. 5. The phrase “and stops” means that no more work is shown by the candidate. 6. Special notes relating to the marking of a particular part of a question are indicated by an asterisk. These notes immediately follow the box containing the relevant solution. 7. The sample solutions for each question are not intended to be exhaustive lists – there may be other correct solutions. 8. Unless otherwise indicated in the scheme, accept the best of two or more attempts – even when attempts have been cancelled. 9. The same error in the same section of a question is penalised once only. 10. Particular cases, verifications and answers derived from diagrams (unless requested) qualify for attempt marks at most. 11. A serious blunder, omission or misreading results in the attempt mark at most. 12. Do not penalise the use of a comma for a decimal point, e.g. €5.50 may be written as €5,50. Page 1 QUESTION 1 Part (a) Part (b) Part (c) 10 marks 20(5, 5, 5, 5) marks 20(5, 5, 5, 5) marks Part (a) (a) A = {a, b, c, d, e} Att 3 Att (2, 2, 2, 2) Att (2, 2, 2, 2) 10 marks Att 3 B = {c, d, f, g} Fill the elements of A and B into the following Venn diagram: A B Part (a) 10 marks Att 3 A B a b e • • • * * dc • • f g • • Only one correct element correctly placed in the Venn diagram merits 4 marks. • Not necessary Slips (-1) S1 Each element incorrectly filled into the diagram. S2 Each element omitted from the diagram. Attempts (3 marks) A1 Totally incorrect filling of the Venn diagram Worthless (0) W1 No filling of the Venn diagram. Page 2 Part (b) 20(5, 5, 5, 5) marks 1(b) U is the universal set. P = {1, 4, 5, 7} Att (2, 2, 2, 2) U P Q •5 Q = {4, 6, 7, 9, 10} •4 R = {1, 7, 8, 10} •6 7 •9 •10 •1 •8 •2 •3 R Part(b)(i) (i) List the elements of Q ∪ R. 5 marks Att 2 Part(b)(i) Q ∪ R = {1, 4, 6, 7, 8, 9, 10} 5 marks Att 2 Blunders (-3) B1 Any incorrect set of the elements of Q and R other than the misreading as below. Misreadings (-1) M1 Q ∩ R giving {7, 10}. Attempts (2 marks) A1 2 or 5 or 3 appear in the answer. Part (b) (ii) (ii) List the elements of Q \ ( P ∪ R ). 5 marks Att 2 Part (b) (ii) Q \ ( P ∪ R ). = {6, 9} 5 marks Att 2 Blunders (-3) B1 Any incorrect set of elements of P and Q and R other than the misreading as below. Misreadings (-1) M1 ( P ∪ R ) \ Q giving {1, 5, 8}. Q \ ( P ∩ R ) giving {4,6,9,10} or ( P ∩ R ) \ Q giving{1}. Attempts (2 marks) A1 2 or 3 appear in the answer. Page 3 Part (b) (iii) 5 marks Att 2 (iii) List the elements of P′, the complement of the set P. Part (b) (iii) P′ = {2,3,6,8,9,10} 5 marks Att 2 Slips (-1) S1 Each correct element omitted and/or each incorrect element included. (Max -3) Attempts (2 marks) A1 P or any proper subset of P. Part (b) (iv) (iv) Write down # R. 5 marks Att 2 Part (b) (iv) 5 marks Att 2 4 Blunders (-3) B1 Incorrect #R ≤ 10. (See M2) Misreadings (-1) M1 R= {1, 7, 8, 10} M2 #R' = 6. Attempts (2 marks) A1 Uses phrase “number of elements” or “cardinal number”. A2 #R = 26 or 560. Page 4 Part (c) 1(c) Part(c) (i) 20(5, 5, 5, 5) marks Att (2, 2, 2, 2) There are 30 students in a class. 21 own a mobile phone (M) and 12 own a computer (C). 7 own both a mobile phone and a computer. 5 marks (i) Represent this information in the Venn diagram below. Part(c) (i) Att 2 5 marks Att 2 M C [14] [7] [4] Blunders (-3) B1 Incorrect Venn diagram subject to S1 below. Slips (-1) S1 Numerical errors where work is clearly shown. Attempts (2 marks) A1 Any one correct/relevant entry. Page 5 [5] Part(c) (ii) 5 marks (ii) How many students own a mobile phone but not a computer? Att 2 Part(c) (ii) * * * 5 marks Att 2 14 A correct answer written in the space provided takes precedence over an incorrect Venn diagram. Accept candidates work from previous part c (i). If no work appears here, award 2 marks if correct answer appears in Venn Diagram. Blunders (-3) B1 Any incorrect use of the given numbers or the numbers from the candidates incorrect Venn diagram. [ Subject to S1]. Slips (-1) S1 Numerical errors where work is clearly shown. Misreadings (-1) M1 C\M Part(c) (iii) 5 marks (iii) How many students own neither a mobile phone nor a computer? Att 2 Part(c) (iii) Att 2 * * * 5 marks 4 A correct answer written in the space provided takes precedence over an incorrect Venn diagram. Accept candidates work from previous parts (c) (i), (c) (ii). If no work appears here, award 2marks if correct answer appears in Venn Diagram. Blunders (-3) B1 Incorrect Venn diagram.[ Subject to Second *above]. B2 Any incorrect use of the given numbers or numbers from the previous work. [Subject to Second *above]. Slips (-1) S1 Numerical errors where work is clearly shown. Page 6 Part(c) (iv) Part(c) (iv) * * 5 marks (iv) How many students do not own a mobile phone? 5 marks 9 Att2 Att2 A correct answer written in the space provided takes precedence over an incorrect Venn diagram. Accept candidates work from previous parts (c) (i), (c) (ii), and (c) (iii). Blunders (-3) B1 Incorrect Venn diagram. [ Subject to Second *above]. B2 Any incorrect use of the given numbers or numbers from the previous work. [Subject to Second * above]. Slips (-1) S1 Numerical errors where work is clearly shown Page 7 QUESTION 2 Part (a) Part (b) Part (c) 10 marks 20(5, 10, 5) marks 20(5, 5, 10) marks Att 3 Att (2, 3, 2) Att (2, 2, 3) Part (a) 10 marks (a) In a school of 646 pupils the ratio of girls to boys is 9:8. Find the number of girls and the number of boys in the school. Att 3 Part (a) Att 3 " 10 marks 9 + 8 = 17 9 parts : 8 parts 9 x :8 x 646 ⇒ = 38 17 Girls = 38 × 9 = 342 Boys = 38 × 8 = 304 ⇒17 x = 646 ⇒ x = 38 ⇒ 9 x = 342 ⇒ 8 x = 304 1 = 38 17 9 ⇒ = 342(Girls) 17 ⇒ 646 − 342 = 304( Boys). Blunders (-3) B1 Correct answers without work. " B2 Divisor = 8 or 9 only and continues. B3 Incorrect multiplier or fails to multiply. (each time) B4 Error in transposition (x method). B5 Fails to find second number. (Number of boys or girls only). B6 Adds instead of subtracting e.g. 646 + 342 = 988. Slips (-1) S1 Numerical errors to a max of 3 . Attempts (3 marks) 646 646 and/or and st ops. A1 Divisor ≠ 17 e.g. 9 8 A2 Indicates 17 parts or 9 parts or 8 parts or 9/17 or 8/17 or 9+8=17 only and stops. A3 5814:5168 only. i.e. multiplies 646 by 9 and by 8. A4 Divide by 2 and stops or continues. (Oversimplification). A5 Both answers added to equal 646. (If no work shown). Worthless (0) W1 Incorrect answer without work. Page 8 Part (b) (i) 5 marks 2(b) (i) On a day when €1 = $ 1⋅ 21 , find the value in euro of $6655. Att 2 Part (b) (i) Att2 " * 5 marks $1.21 = €1 1 ⇒ $1 = € 1.21 €1= $1.21 € ? = $6655 6655 = €5500 ?= 1.21 ⇒ $6655 = 6655 × No penalty for the omission of € or $ symbols. Blunders (-3) B1 Correct answer without work. " B2 Incorrect multiplier i.e.6655 × 1.21=8052.55 1.21 121 B3 Incorrect ratio or . 6655 665500 B4 Decimal error. 6655 B5 Fails to finish, leaves as and stops. 1.21 Slips (-1) S1 Numerical errors to a max of 3. S2 Rounds off too early. i.e. (0.83). Attempts (2 marks) 1 A1 $1= € and stops. 1.21 Worthless (0) W1 Adds or subtracts 6655 and 1.21. W2 Incorrect answer without work. Page 9 1 = €5500 1.21 Part (b) (ii) 10 marks 2 (b) (ii) By rounding each of these numbers to the nearest whole number, 4 ⋅ 368 + 10 ⋅ 92 estimate the value of . 3 ⋅ 12 Att3 Part (b) (ii) Att3 " 10 marks 4 ⋅ 368 + 10 ⋅ 92 is approximately equal to: 3 ⋅ 12 4 + 11 15 = 3 * * * = 5 3 4 + 11 and stops ⇒ 4 marks. 3 No penalty if the intermediate step between approximations and final answer not 15 not shown. shown.i.e. 3 4.368 + 10.92 Special Case: = 4.9 ⇒ 3 marks. 3.12 Blunders (-3) B1 Correct answer without work. " B2 Error(s) in rounding off to the nearest whole number. B3 Decimal error in calculation of approximate value. B4 An arithmetical operation other than indicated. 4 B5 + 11 or similar and continues. 3 Slips (-1) S1 Numerical errors to a max of 3. Attempts (3 marks) A1 Only one or two approximations made to the given numbers & stops. Page 10 Part (b) (iii) Part(b) 5marks (iii) Using a calculator, or otherwise, find the exact value of Part (b) (iii) Att2 4 ⋅ 368 + 10 ⋅ 92 . 3 ⋅ 12 5marks 15.288 4 ⋅ 368 + 10 ⋅ 92 = = 4.9 3.12 3 ⋅ 12 Blunders (-3) B1 Decimal error. 4.368 B2 Treats as: + 10.92 = 1.4 + 10.92 = 12.32 .[ B1 may occur]. 3.12 10.92 B3 Treats as: 4.368 + = 4.368 + 3.5 = 7.868 .[ B1 may occur]. 3.12 4.368 −10.92 B4 Treats as: = − 2.1 [B1 may occur]. 3.12 4.368 ×10.92 B5 Treats as: = 15.288 .[B1 may occur]. 3.12 Slips (-1) S1 Numerical errors to a max of 3. Attempts (2 marks) A1 Some correct calculation done. Page 11 Att2 Part (c) (i) 5 marks Att 2 ( ) 3 Using a calculator, or otherwise, find the exact value of 4 2 . 2(c) (i) Part(c) (i) 5marks (4 ) = 4096 Att2 2 3 * 46 and stops. = 4 marks. Blunders (-3) B1 Mishandles ( 42 ) .e.g. 45 = 1024, 3 ( 4 ) = 8, ( 4 ) = 2.5198421. 3 3 2 Attempts (2 marks) 3 A1 ( 4 ) = 64. A2 ( 4) A3 4 × 3× 2 = 24 . 2 = 16. Part (c) (ii) 5 marks Using a calculator, or otherwise, multiply 65 ⋅ 5 by 40 and express your answer in the form a × 10 n , where 1 ≤ a < 10 and n ∈ Z. Att 2 Part (c) (ii) Att 2 " 5 marks 65.5 × 40 = 2620 = 2.62 ×103 Blunders (-3) B1 Correct answer without work. " B2 Decimal error. B3 Incorrect format, where a ≤1 or a ≥10 and n ∉ Z . Slips (-1) S1 Numerical errors to a max of 3. S2 Rounds off to 3 × 103 , 2.6 × 103 . S3 Incorrectly rounds off. e.g. 2.7 × 103 also attracts S2. Attempts (2 marks) A1 2620 and stops. A2 Any relevant step.e.g. Partial multiplication. Page 12 Part (c) (iii) 10 marks (iii) Using a calculator, or otherwise, evaluate 86 ⋅ 49 1 × 7 ⋅ 48 . + 0 ⋅ 0125 15 ⋅ 5 Give your answer correct to two decimal places. Att 3 Part (c) (iii) Att3 " 10 marks 9.3 = 80 + × 7.48 15.5 = 80 + 0.6 × 7.48 = 80 + 4.488 = 84.488 = 84.49 * Correct answer (without work) incorrectly rounded off ⇒ 6 marks Blunders (-3) B1 Correct answer without work. " 1 B2 Mishandles . 0 ⋅ 0125 B3 Mishandles 86.49 9.3 or candidate's equivalent from previous work. B4 Error in 15.5 B5 Error in multiplication of 0.6 × 7.48 or candidate's equivalent from previous work. B6 Decimal error. 1 86 ⋅ 49 + × 7 ⋅ 48 .= 602.888. B7 Adds before Multiplication: 0 ⋅ 0125 15 ⋅ 5 B8 Incorrect denominator. B9 Incorrect numerator. B10 Works as 80 × 7.48 + 0.6 = 599 . B11 Multiplies instead of adds. Slips (-1) S1 Numerical errors to a max of 3. S2 Each premature rounding off to a max of 3. S3 Fails to round off or rounds off incorrectly when giving final answer. Attempts (3 marks.) A1 Any relevant step e.g. 1 = 80, 0 ⋅ 0125 86.49 = 9.3 Page 13 QUESTION 3 Part (a) Part (b) Part (c) Part (a) 3. (a) 10 marks 20(10, 10) marks 20(5, 5, 5, 5) marks Att 3 Att (3, 3) Att (2, 2, 2, 2) 10 marks Find the total cost of the following bill: Att 3 " 6 litres of milk at €1.05 a litre 3 loaves of bread at €1 .20 a loaf 5 apples at 65c each Part (a) 10 marks 1.05 × 6 = 6.3 1.20 × 3 = 3.6 OR 0.65 × 5 = 3.25 Total Cost = €13.15 1.05 + 1.05...6 Times = 6.30 + 1.20 + 1.20....3Times = 3.60 + 0.65 + 0.65....5 Times = 3.25 Total Cost = €13.15 * Accept 1315, 13.15. * No penalty for missing € symbol. * Adds 1.05 + 1.20 + 0.65 = 2.90 and stops ⇒ 3 marks. (Oversimplification). Blunders (-3) B1 Correct answer without work. " B2 Each missing product when finding items cost e.g. 1.05 not multiplied by 6. B3 Each missing item when finding total cost e.g. cost of bread omitted. B4 Fails to find total cost i.e. no addition. B5 Operation other than addition of items to find total cost. B6 Decimal error e.g. 131.5 (Note: First *). Slips (-1) S1 Numerical errors to a max of 3. Attempts (3 marks) A1 Any attempt at addition /multiplication. Worthless (0) W1 Incorrect answer without work. Page 14 Att 3 Part (b) (i) 10marks 3(b) (i) V.A.T .at 21% is added to a bill of €750. Calculate the total bill. Part (b) (i) 10marks Method 1 100% = 750 Method 2 750 1% = 100% = 750 100 750 750 121% = × 121 1% = 100 100 = 7.5 ×121 750 × 21 = 157.50 21% = 100 Total bill = €907.5 Total Bill =157.5 + 750 = €907.50 Method 3 " 21 Method 4 100 750 ×1.21 = 907.5 21 V . AT . .= × 750. Total bill = €907.50 100 Total bill =157.5 + 750 = €907.5 * €157.50 (without work) and stops ⇒ 4 marks. * No penalty for missing € symbol. Blunders (-3) B1 Correct answer without work. " 121 21 B2 Inverts or and continues (giving answers 619.83 or 3571.43). 100 100 B3 Mishandles 21%. e.g.750× 21 or 750 ÷ 21 (750 must be used). B4 750 taken as 121% B5 No addition of V.A.T. (as per candidates work) to the bill. B6 Subtraction of V.A.T. ( as per candidates work) from the bill. 21% = Slips (-1) S1 Numerical errors to a max of 3. Attempts (3 marks) 21 and stops. A1 100 A2 100% = 750 and stops. 750 A3 and stops. 100 21 A4 100 × and stops. 750 750 A5 and stops. 21 A6 Use of any other % Page 15 Att 3 Att 3 Part (b) (ii) (ii) 10marks €7450 is invested at 2 ⋅ 6 % per annum. What is the amount of the investment at the end of one year? Att 3 Part (b) (ii) 10marks Att 3 "(ii) 7450 100 2.6% = 74.50 × 2.6 1% = P × R 7450 × 2.6 = = 193.7 100 100 Amount = €7643.70 I= 7450 × 1 ⋅ 026 = 7643.7 Amount = €7643.7 Interest = €193.70 Amount = €7643.70 * * €193.70 (without work) and stops ⇒ 4 marks. No penalty for missing € symbol. Blunders (-3) B1 Correct answer without work. " B2 Mishandles 2.6%. e.g. 7450 × 2.6 or 7450 ÷ 2.6 (7450 must be used). B3 Decimal error (once only). B4 Stops at interest i.e. fails to calculate amount. B5 Subtracts to calculate amount. 7450 × 2.6 . B6 Illegal cancellation(s) in 100 B7 1 ⋅ 026 = 1 ⋅ 26. Slips (-1) S1 Numerical errors to a max of 3. Attempts (3 marks) A1 Correct formula with or without substitution and stops. A2 Some use of 100 in attempt to find percentage e.g. 2.6% = Worthless (0) W1 Incorrect answer without work. Page 16 2.6 and stops. 100 Part (c) 20(5, 5, 5, 5) marks 3(c) John’s weekly wage is €730. He pays income tax at the rate of 20% on the first €440 of his wage and income tax at the rate of 42% on the remainder of his wage. John has a weekly tax credit of €65. Att (2, 2, 2, 2) Part (c) (i) 5 marks (i) Find the tax on the first €440 of his wage, calculated at the rate of 20%. Att 2 Part (c) (i) Att 2 5 marks "(i) 1% = 4.4 20% = 88 Tax = €88 * Tax = 440 × 20 = €88 100 440 × 0 ⋅ 2 = €88 . No penalty for missing € symbol. Blunders (-3) B1 Correct answer without work. " B2 Mishandles 20%, e.g. 440 × 20 = 8800 or 440 ÷ 20 = 22. B3 Uses €730 instead of €440. B4 Decimal error. Slips (-1) S1 Numerical errors to a max of 3 Attempts (2 marks) 20 A1 Some use of 100 in attempt to find percentage e.g. 20% = 100 and stops Worthless (0) W1 Incorrect answer without work Page 17 Part (c) (ii) 5 marks (ii) Find the tax on the remainder of his wage, calculated at the rate of 42%. Att 2 Part (c) (ii) Att 2 " (ii) 1% = 2 ⋅ 9 5 marks Remainder of wage = €730 − €440 = €290 Tax = 290 × 42 = €121.8 100 or 290 × 0 ⋅ 42 = €121.8 42% = 121.8 Tax = €121.8. * No penalty for missing € symbol. Blunders (-3) B1 Correct answer without work. " B2 Mishandles 42%, e.g. 290 × 42 or 290 ÷ 42 . [No penalty if already penalised in (c) (i)]. B3 Uses €730 or €440 instead of €290. B4 Decimal error. B5 730 - 440 = 290 and stops. or Slips (-1) S1 Numerical errors to a max of 3. Attempts (2 marks) 42 and stops. A1 Some use of 100 in attempt to find percentage e.g. 42% = 100 Worthless (0) W1 Incorrect answer without work. Part (c) (iii) (iii) Hence calculate John’s gross tax. Part (c) (iii) 5 marks Att 2 5 marks Att 2 " (iii) John’s gross tax = €88 + €121.80= €209.80 * Allow candidates incorrect answers from parts (i) and (ii). * No penalty for missing € symbol. Blunders (-3) B1 Correct answer without work. " B2 €88 − €121.80 = - €33.80 B3 Misuse of tax credit. Slips (-1) S1 Numerical errors to a max of 3. Attempts (2) A1 Answer from c (i) and /or c (ii) written in this part. Worthless (0) W1 Incorrect answer without work Page 18 Part (c) (iv) (iv) 5 marks Calculate John’s take home pay. Att 2 Part (c) (iv) 5 marks Att 2 " * * Tax payable = €209.80 - €65 Take home pay = €730 - €144.80 Take home pay = €585.20 Allow candidate’s incorrect gross tax figure from (c) (iii). No penalty for missing € symbol. Blunders (-3) B1 Correct answer without work. " B2 Misuse of tax credit e.g. 209.80 + 65 = 274.80. B3 Decimal error. Slips (-1) S1 Numerical errors to a max of 3. Attempts (2) A1 Answer from c (iii) written in this part. Worthless (0) W1 Incorrect answer without work. Page 19 QUESTION 4 Part (a) Part (b) Part (c) Part (a) (i) 10(5, 5) marks 20(10, 10) marks 20(5, 5, 5, 5) marks 10(5, 5) marks If a = 2 and b = 5 , find the value of 3a + b Part (a) (i) " * * Att (2, 2) Att (3, 3) Att (2, 2, 2, 2) 5 marks (i) Att 2,2 Att 2 3a + b = 3 ( 2 ) + 5 = 6 + 5 = 11 6 + 5 ⇒ 4 marks. One substitution coupled with an implied substitution leading to correct answer ⇒ 5 marks.e.g. = 3a +5 = 11 Blunders (-3) B1 Correct answer without work. " B2 Leaves 3(2) in the answer. B3 Breaks order i.e. [ 3 ( 2 + 5 ) = 21 ]. B4 Treats 3(2) as 5 or 32. Slips (-1) S1 Numerical errors to a max of 3. S2 Values of a and b interchanged. Misreadings (-1) M1 Incorrect numerical substitution for either a or b, but not both, and continues. (See W1) Attempts (2 marks) A1 Incomplete substitution and stops e.g. 3a + 5, Worthless (0) W1 Incorrect substitution for both a and b. Page 20 Part (a) (ii) 10(5, 5) marks If a = 2 and b = 5 , find the value of ab − 3 Part (a) (ii) " * 5 marks (ii) Att 2, 2 Att 2 ab − 3 = 2 ( 5 ) − 3 = 10 − 3 = 7 10 − 3 ⇒ 4 marks. Blunders (-3) B1 Correct answer without work. " B2 B3 Leaves 2(5) in the answer. Breaks order i.e. [ 2 ( 5 − 3) = 4 ]. B4 Treats 2(5) as 25, 7, or 52. [Do not penalise if already penalised in part (a) (i) or work is shown in part (a) (i).] Slips (-1) S1 Numerical errors to a max of 3. Misreadings (-1) M1 Incorrect numerical substitution for either a or b but not both, and continues. (See W1) Attempts (2 marks) A1 Incomplete substitution and continues or stops e.g. 2b − 3, 5a − 3 Worthless (0) W1 Incorrect substitution for both a and b. Page 21 Part (b) (i) 4(b) (i) Solve the equation Part (b) (i) 10marks 2 ( x − 3) = x +1. Att 3 10marks Att 3 2 ( x − 3) = x + 1 " 2 x − 6 = x +1 2 x − x = 1+ 6 x =7 Blunders (-3) B1 Correct answer without work. " B2 Error in distributive law and continues,e.g. 2 x − 3 = x + 1, 2 x − 6 = 2 x + 2 (once only). B3 Error(s) in transposition. B4 Combines “ x ”to “numbers” and continues. e.g. 2 x − 6 = − 4 x . B5 Fails to finish. Slips (-1) S1 Numerical errors to a max of 3. Attempts (3 marks) A1 Any correct step. Worthless (0) W1 Combines “ x ”to “numbers” and stops. Page 22 Part (b) (ii) 10marks Att 3 Multiply ( x − 5) by (2 x + 3) . Write your answer in its simplest form. Part (b) (ii) " 10marks ( x − 5)( 2 x + 3) = x ( 2 x + 3) − 5 ( 2 x + 3) = 2 x 2 + 3 x − 10 x − 15 = 2 x 2 − 7 x −15 * First line = x ( 2 x + 3) − 5 ( 2 x + 3) or 2 x ( x − 5 ) + 3 ( x − 5 ) = 4 marks. Blunders (-3) B1 Correct answer without work. " B2 Error(s) in distribution. B3 Combining unlike terms. B4 Fails to group or groups incorrectly. Slips (-1) S1 Numerical errors to a max of 3. Attempts (3 marks) A1 Any correct multiplication. A2 Oversimplification of question. A3 A correct step. Worthless (0) W1 ( x − 5 ) ± ( 2 x + 3) stops or continues. W2 Combining unlike terms before attempting multiplication and stops. Page 23 Att 3 Part(c) (i) 10(5, 5) marks Att (2, 2) The cost of 2 jumpers and 3 shirts is €84. The cost of 4 jumpers and 1 shirt is €78. Let €x be the cost of a jumper and let €y be the cost of a shirt. (i) Write down two equations, each in x and y to represent the above information. Write down two equations " 10(5, 5) marks First equation: 2 x + 3 y = 84 Second equation: 4 x + y = 78 * Special Case: 2 + 3 = 84, 4 + 1 = 78. Award 7 marks. Blunders (-3) B1 Correct answer without work. " Apply to both equations Slips (-1) S1 Incorrect coefficient of x (other than zero). S2 Incorrect coefficient of y (other than zero). S3 Incorrect constant. Attempts (2 marks) A1 Any effort at a linear equation in x only or a linear equation in y only. A2 2 x only or 4 x only or 3 y only appear. Page 24 Att(2,2) Part(c) (ii) 5 marks ii) Solve these equations to find the cost of a jumper and the cost of a shirt. Att 2 Part(c) (ii) Att 2 5 marks 2 x + 3 y = 84 4 x + y = 78 2 x + 3 y = 84 4 x + y = 78 " 2 x + 3 y = 84 −12 x − 3 y = − 234 or − 4 x − 6 y = − 168 4 x + y = 78 −10 x = − 150 x = €15 y = €18 * * * * − 5 y = − 90 y = 78 − 4 x 2 x + 3 ( 78 − 4 x ) = 84 or 5 y = 90 y = €18 2 x + 234 − 12 x = 84 − 10 x = − 150 x = €15 y = €18 x = €15 Apply only one blunder deduction (B2 or B3) to any error(s) in establishing the first equation in terms of x only or the first equation in terms of y only. Finding the second variable is subject to a maximum deduction of (-3). If the candidates equations in (c)(i) are such that they lead to an over simplification of the work in (c)(ii) then Attempt marks apply at most. No penalty for missing € symbol. Blunders (-3) B1 Correct answers without work. " B2 Error(s) in establishing the first equation in terms of x only [ −10 x = − 150 ] or the first equation in terms of y only [ −5 y = − 90 ] through elimination by cancellation. B3 Error(s) in establishing the first equation in terms of x only [ 4 x = 60 ] or the first equation in terms of y only [ 3 y = 54 ] through elimination by substitution. B4 Errors in transposition in solving the first one variable equation. B5 Errors in transposition when finding the second variable. B6 Incorrect substitution when finding second variable. B7 Finds one variable only. Slips (-1) S1 Numerical errors to a max of 3 Attempts (2 marks) A1 Attempt at transposition and stops. A2 Multiplies either equation by some number and stops. Page 25 Part(c) (iii) (iii) Verify your result. 5marks Att2 Part(c) (iii) 5marks Att2 " 2(15) + 3(18) = 84 4(15) + 18 = 78 * Accept candidates answers from previous work in this part. Blunders (-3) B1 Correct answers without work. " B2 Verifies only one equation. B3 Error in substitution to either equation. B4 Forces equality Slips (-1) S1 Numerical errors to a max of 3. S2 Conclusion missing. Attempts (2 marks) A1 Substitutes into one equation and stops. A2 Writes the equations in this section. A3 Answers from (c) (ii) written in this part. Page 26 QUESTION 5 Part (a) Part (b) Part (c) 10 marks 20 (5, 5, 5, 5) marks 20 (10, 5, 5) marks Att 3 Att (2, 2, 2, 2) Att (3, 2, 2) Part (a) 10 marks Write in its simplest form 4( x + 3) + 2(5 x + 4) . Att 3 Part (a) Att3 " * * 10 marks 4 x + 12 + 10 x + 8 14 x + 20 Stops after correct removal of brackets ⇒ 7 marks. Ignore excess work 2 ( 7 x + 10 ) Blunders (-3) B1 Correct answer without work. B2 Error(s) in distribution. B3 Combining unlike terms. B4 Fails to group like terms. " Slips (-1) S1 Numerical errors to a max of 3. Misreadings (-1) 4( x + 3) × 2(5 x + 4) and continues. M1 Attempts (3 marks) A1 Any correct multiplication. Worthless (0) W1 Combining unlike terms before attempting multiplication and stops. Page 27 Part (b) (i) (i) Factorise: 5 marks xy + wy Att 2 Part (b) (i) (i) 5 marks y(x + w) Att 2 Blunders (-3) B1 An incorrect factor. B2 Removes factor incorrectly. Attempts (2 marks) A1 Indication of common factor. e.g. underline y 's and stops. Part (b) (ii) (ii) Factorise: 5 marks ax − ay + bx − by Part (b) (ii) " (ii) 5 marks ax − ay + bx − by a ( x − y) + b( x − y) Att 2 ax + bx − ay − by x (a + b) − y (a + b) or ( x − y )( a + b ) * Att 2 ( a + b )( x − y ) Accept (with or without brackets) for 5 marks any of the following ( x − y ) and ( a + b ) . [The word and is written down.] ( x − y ) or ( a + b ) . ( x − y) , (a + b) . [The word or is written down.] [A comma is used] Blunders (-3) B1 Correct answer without work. " B2 Stops after first line of correct factorisation. e.g. a ( x − y ) + b ( x − y ) or equivalent. B3 B4 Error(s) in factorising any pair of terms. Incorrect common factor and continues. e.g. a ( x − y ) + b ( x + y ) = ( a + b )( x − y ) Slips (-1) S1 ( a + b ) ± ( x − y ) S2 Correct first line of factorisation but ends as ab ( x − y ) . Attempts (2 marks) A1 Pairing off, or indication of pairing off, and stops. A2 Correctly factorises any pair and stops. Page 28 Part (b) (iii) Factorise: 5 marks Att 2 5 marks p − 36 Att 2 p 2 − 36 Part (b) (iii) 2 P 2 − 62 (iii) ( p − 6 )( p + 6 ) * Accept (with or without brackets) for 5 marks any of the following ( p + 6 ) and ( p − 6 ) . [The word and is written down.] ( p + 6 ) or ( p − 6 ) . [The word or is written down.] ( p + 6), ( p − 6) [A comma is used] * Quadratic equation formula is subject to slips and blunders.[See 5(c)(i)] Blunders (-3) B1 Incorrect two term linear factors of p 2 − 36 formed from correct (but not applicable) factors of p 2 and ±36 e.g. ( p − 9 )( p + 4 ) . B3 ( 6 + p )( 6 − p ) . ( p − 36 )( p + 36 ) . B4 Incorrect factors of p 2 and/or 36. B2 Slips (-1) S1 Solves p 2 = 36 to give p = 6 and p = −6 and stops. S2 ( p + 6) ± ( p − 6) Attempts (2 marks) A1 Correct factors of p 2 only. A2 Correct factors of 36 or −36 only. A3 p or ± 6 appears. A4 p 2 − 36 = p. p − 6.6 and stops. A5 Mention of the difference of two squares. Page 29 Part (b) (iv) 5 marks Factorise: 4a + 8a (iv) Part (b) (iv) 5 marks 4 a 2 + 8a (iv) * Att2 2 Att2 4a ( a + 2 ) Accept 4a 2 +8a 4 ( a 2 + 2a ) or 4a 2 + 8a or 2 ( 2a 2 + 4a ) 4a 2 + 8a a ( 4a + 8 ) or 2a ( 2a + 4 ) Blunders (-3) B1 An incorrect factor. B2 Stops after some correct effort at factorisation. e.g. 4.a.a + 4.2 a B3 Mathematical blunder 4a 2 =16a 2 & continues. Attempts (2 marks) A1 4a ( a ) and / or 8 ( a ) or effort at brackets. A2 Common factor identified or indicated and stops. e.g. 4 a a + 4 2 a or similar. Page 30 Part (c) (i) (i) Solve the equation: 10 marks x2 - 5x - 14 = 0 Att 3 10 marks Att 3 Part (c) (i) " (iii) x x x 2 − 5 x − 14 = = x 2 − 7 x + 2 x − 14 = 0 = x ( x − 7) + 2 ( x − 7) = 0 +2 −7 ⇒ ( x − 7)( x + 2) = 0 ⇒ x = 7 and x = − 2 or = ( x − 7 )( x + 2 ) = 0 ⇒ x = 7 and x = − 2 x= − ( −5 ) ± ( −5 ) − 4 (1)( −14 ) 2 (1) 2 5 ± 25 + 56 5 ± 9 14 −4 = = and 2 2 2 2 ⇒ x = 7 and x = − 2 ⇒ or Factor Method: B1 Correct answers without work. " B2 Incorrect two term linear factors of. x 2 − 5 x − 14 formed from correct (but inapplicable factors of x 2 or ± 14 . B3 No roots given. B4 Incorrect factors of x 2 and/or ±14. B5 Correct cross method but factors not shown and stops [Note: B3 applies also]. B6 x ( x − 7 ) + 2 ( x − 7 ) or similar and stops. [Note: B3 applies also]. B7 B8 Error(s) in transposition. One root only. Slips (-1) S1 Numerical errors to a max of 3. Attempts (3 marks) A1 Some effort at factorisation. A2 Oversimplification resulting in a linear equation & continues. Worthless (0 marks) W1 x 2 − 5 x = 14 or similar and stops. W2 Trial and error. Page 31 Formula Method Blunders (-3) B1 Correct answers without work." B2 Error in a,b,c, substitution (apply once only). B3 Sign error in substituted formula (apply once only). B4 Error in square root or square root ignored. 5±9 B5 Stops at . 2 B6 Incorrect quadratic formula and continues. B7 One root only. p B8 Roots left in the form q Slips (-1) S1 Numerical errors to a max of 3. Attempts (3 marks) A1 Correct formula and stops. A2 One correct substitution and stops. A3 Oversimplification of formula. Page 32 Part (c) (ii) (ii) Att2 3x + 2 x + 4 as a single fraction. − 4 5 Give your answer in its simplest form. Express Part (c) (ii) " 5 marks 5 marks 3x + 2 x + 4 − 4 5 5 ( 3x + 2 ) − 4 ( x + 4 ) = 20 15 x + 10 − 4 x − 16 = 20 11x − 6 = ( 5 marks ) 20 3x + 2 x + 4 2 x + 6 Zero marks. − = 4 5 9 Blunders (-3) B1 Correct answer without work. " B2 Error(s) in distribution. e.g 5 ( 3 x + 2 ) = 15 x + 2. B3 Mathematical error e.g. 10 -16 =6, -4(4) = 16. B4 Incorrect common denominator and continues. Att2 * B5 Incorrect numerator from candidate's denominator e.g. B6 No simplification of numerator. Slips (-1) S1 Correct common denominator implied. S2 Numerical error to a max of 3. Attempts (2 marks) A1 20 only or a multiple of 20 only appears. Worthless (0) 5x 4 x ⎛ 3x + 2 ⎞ ⎛ x + 4 ⎞ − , or ⎜ W1 ⎟ and stops. ⎟⎜ 4 5 ⎝ 4 ⎠⎝ 5 ⎠ Page 33 4 ( 3x + 2 ) − 5 ( x + 4 ) 20 . Part (c) (iii) (iii) 5 marks Verify your answer to part (ii) by letting x = 6 . Part (c) (iii) 5 marks = " * * Att2 11x − 6 20 11( 6 ) − 6 20 66 − 6 = 20 60 = 20 =3 Att2 3(6) + 2 and − ( 6) + 4 4 5 18 + 2 10 = − 4 5 20 10 = − 4 5 = 5 − 2 = 3 Accept candidates answer from previous section. [May result in inequality]. Accept usage of a value other than 6 for verification. Blunders (-3) B1 Correct answer without work. " B2 Substitutes into one expression only. B3 Manipulation to force equality. Slips (-1) S1 Numerical errors to a max of 3. S2 Conclusion missing if unequal. Attempts (2marks) A1 Writes answer from previous part in this section. A2 Substitutes a value into one expression and stops. Page 34 QUESTION 6 Part (a) Part (b) Part (c) 10 (5, 5) marks 30 (20, 10) marks 10 (5, 5) marks Part (a) (i) (i) f ( x) = 2 x − 1. Part (a) (i) " 5 marks Find: f (4) Att 2 5 marks f (4) = 2(4) − 1 Att2 (i) = 8 −1 =7 Blunders (-3) B1 B2 Att (2, 2,) Att (7, 3) Att (2, 2) Correct answer without work. " Mathematical error. e.g. ( 2 )( 4 ) = 24, Slips (-1) S1 Numerical errors to a max of 3. Misreadings (-1) M1 Correctly substitutes in any number other than 4 and continues. Attempts (2marks) A1 Treats as equation and continues or stops. Worthless (0) W1 Ignores x giving 2 −1 = 1. W2 4 [ f ( x) ] = 8 x − 4 Page 35 Part (a) (ii) (ii) Part (a) (ii) " 5 marks Att2 5 marks f (−5) = 2(−5) − 1 Att2 Find: f ( −5) (ii) Blunders (-3) B1 Correct answer without work. work is shown in part (a) (i).] B2 Mathematical error. = −10 − 1 = −11 "[Do not penalise if already penalised in part (a) (i) or Slips (-1) S1 Numerical errors to a max of 3. Misreadings (-1) M1 Substitutes in any negative number other than -5 and continues. Attempts (2marks) A1 Treats as equation and continues or stops. A2 Substitutes in any positive number other than 4. Worthless (0) W1 Ignores x giving 2 −1 = 1. W2 −5 [ f ( x) ] = −10 x + 5 Page 36 Part (b) Table Draw the graph of the function 20 marks Att 7 f : x → 1 + 4 x − x2 in the domain −1≤ x ≤ 5 where x ∈ R. Part (b) Table 20 marks " f (−1) = 1 + 4 ( −1) _ f (0) = 1 + 4 ( 0) _ f (1) = 1 + 4 (1) _ f (2) = 1 + 4 ( 2) _ f (3) = 1 + 4 ( 3) _ f (4) = 1 + 4 ( 4) _ f (5) = 1 + 4 ( 5) _ Att7 ( −1) 2 ( 0) 2 (1) 2 ( 2) 2 ( 3) 2 ( 4) 2 ( 5) 2 = -4 = 1 = 4 = 5 = 4 = 1 = -4 or x 1 4x − x2 f(x) * -1 1 -4 -1 -4 0 1 0 0 1 1 1 4 -1 4 2 1 8 -4 5 3 1 12 -9 4 4 1 16 -16 1 Error in each row or column attracts a maximum deduction of 3 marks. Blunders (-3) B1 B2 B3 B4 B5 B6 B7 B8 5 1 20 -25 -4 − x 2 taken as x 2 . − x 2 taken as −2x all the way. [In row headed − x 2 by candidate] + 4 x taken as + 4 all the way. [In row headed + 4 x by candidate] 1 calculated as x all the way.[In row headed 1 by candidate] Adds in top row when evaluating f ( x) . Omits ‘1’ row or omits ‘4 x ’ row. Omits a value in the domain. Each incorrect image without work. Page 37 Slips (-1) S1 Numerical errors to a max of 3 Misreadings (-1) M1 Misreads ‘4 x ’ as ‘-4 x ’ and places ‘-4 x ’ in the table M2 Misreads ‘ + 1 ’ as ‘ − 1 ’ and places ‘ − 1 ’ in the table. Attempts (7marks) A1 Omits − x 2 row from table or treats − x 2 as ±x. A2 Table with only f (x) = ± x 2 A3 Any effort at calculating point(s). A4 Only one point calculated and stops. Page 38 Part (b) Graph * * * * 10 marks Att3 Accept candidate's values from previous work. Only one point graphed correctly ⇒ Att 7 + Att 3 Correct graph but no table ⇒ full marks i.e. 30 marks. Accept reversed co-ordinates if (i) if axes not labelled or (ii) if axes are reversed to compensate (see B1 below) Blunders (-3) B1 Reversed co-ordinates plotted against non-reversed axes (once only) [See 4th * above]. B2 Scale error (once only). B3 Points not joined or joined in incorrect order (once only). Slips (-1) S1 Each point of candidate graphed incorrectly. S2 Each point from table not graphed [See 2nd * above]. Attempts (3 marks) A1 Graduated axes (need not be labelled). Page 39 Part (c) (i) 5 marks (i) Draw the axis of symmetry of the graph drawn in 6 (b) above. " (c) (i) * * Work to be shown on the graph. 5 marks Att 2 Accept any vertical line (parallel to candidate's y-axis) within a tolerance of (± 0.25). A candidate's incorrect graph may merit full marks for this section subject to the same tolerance) Blunders (-3) B1 Any vertical line (parallel to the candidate's y-axis) outside of tolerance. B2 Marks x = 2 on the x -axis and stops. B3 States x = 2 but no line is indicated on the graph. Attempts (2marks) A1 Any attempt at axial symmetry of f ( x ) . A2 Att 2 y -axis as the axis of symmetry (See B1) Page 40 Part (c) (ii) 5 marks Use the graph drawn in 6 (b) to estimate the value of f (x) when x = 3 ⋅ 5. (ii) " Att 2 Work to be shown on the graph and answer to be written here. 2.75 Part (c) (ii) * * 5 marks Att2 Correct answer (clearly consistent with graph) inside tolerance without graphical indication ⇒ 2 marks. A candidates incorrect graph can earn up to full marks for this section (see tolerance) Page 41 Blunders (-3) B1 Correct answer without work. " B2 Answer on diagram but outside of tolerance ( ± 0 ⋅ 25 ). B3 Fails to write down the answer. Attempts (2 marks) A1 Algebraic evaluation or calculator. A2 Marks 3 ⋅ 5 in any way on either axis and stops. Worthless (0) W1 Answer outside of tolerance without graphical indication. W2 f ( 0 ) =1 as answer. Page 42 MARKING SCHEME JUNIOR CERTIFICATE EXAMINATION 2005 MATHEMATICS – ORDINARY LEVEL – PAPER 1 GENERAL GUIDELINES FOR EXAMINERS 1. Penalties of three types are applied to candidates’ work as follows: • Blunders - mathematical errors/omissions (-3) • Slips - numerical errors (-1) • Misreadings (provided task is not oversimplified) (-1). Frequently occurring errors to which these penalties must be applied are listed in the scheme. They are labelled: B1, B2, B3,…, S1, S2,…, M1, M2,…etc. These lists are not exhaustive. 2. When awarding attempt marks, e.g. Att(3), note that • any correct, relevant step in a part of a question merits at least the attempt mark for that part • if deductions result in a mark which is lower than the attempt mark, then the attempt mark must be awarded • a mark between zero and the attempt mark is never awarded. 3. Worthless work is awarded zero marks. Some examples of such work are listed in the scheme and they are labelled as W1, W2,…etc. 4. The phrase “hit or miss” means that partial marks are not awarded – the candidate receives all of the relevant marks or none. 5. The phrase “and stops” means that no more work is shown by the candidate. 6. Special notes relating to the marking of a particular part of a question are indicated by an asterisk. These notes immediately follow the box containing the relevant solution. 7. The sample solutions for each question are not intended to be exhaustive lists – there may be other correct solutions. 8. Unless otherwise indicated in the scheme, accept the best of two or more Attempts – even when Attempts have been cancelled. 9. The same error in the same section of a question is penalised once only. 10. Particular cases, verifications and answers derived from diagrams (unless requested) qualify for attempt marks at most. 11. A serious blunder, omission or misreading results in the attempt mark at most. 12. Do not penalise the use of a comma for a decimal point, e.g. €5.50 may be written as €5,50. QUESTION 1 Part (a) Part (b) Part (c) 10 (5, 5) marks 20 (5, 5, 5, 5) marks 20 (5, 5, 5, 5) marks Part (a)(i) 5 marks (i) Att (2, 2) Att (2, 2, 2, 2) Att (2, 2, 2, 2) Att 2 P = {x, y, w} Write down a subset of P that has one element (i) {x} or {y} or {w} Blunders (−3) B1 Any inapplicable subset of P. [proper or improper] Misreadings (−1) M1 Subsets of P with two elements. Part (a)(ii) (ii) 5 marks P = {x, y, w} Write down a subset of P that has two elements. (ii) {x, y} or {x, w} or {y, w} Blunders (−3) B1 Any inapplicable subset of P. (proper or improper) Misreadings (−1) M1 Subsets of P with one element. Page 2 of 37 Att 2 Part (b) 20 (5, 5, 5, 5) marks Att( 2, 2, 2, 2) U U is the universal set. A 8• A = {1, 2, 4, 8}, the set of divisors of 8. •6 •1 •2 •4 B = {1, 2, 3, 4, 6, 12}, the set of divisors of 12. C = {1, 2, 4, 5, 10, 20}, the set of divisors of 20. •5 •12 •7 •10 •20 Part (b) (i) (i) B •3 •9 C 5 marks Att 2 A ∩ C ={1, 2, 4} Blunders(−3) B1 Any incorrect set of the elements of U other than the misreading as below. Misreadings(−1) M1 A ∪ C giving {1, 2, 4, 5, 8, 10, 20}. Part (b) (ii) 5 marks Att 2 B′ = {5, 7, 8, 9, 10, 20} (ii) Slips(−1) S1 Each correct element omitted and/or each incorrect element included. Attempts (2 marks) A1 B or any proper subset of B. Part (b) (iii) (iii) 5 marks C \ ( A ∩ B ) = {5, 10, 20} Blunders (−3) B1 Any incorrect set of the elements of U other than the misreading as below. Misreadings (−1) M1 ( A ∩ B ) \ C giving the Null Set.(Ø) Page 3 of 37 Att 2 Part (b) (iv) (iv) 5 marks Using the Venn diagram above, or otherwise, find the highest common factor of 8, 12 and 20. Att 2 (iv) H.C.F. = 4 4 is the highest factor in A ∩ B ∩ C. Common factors are 1, 2, 4 ⇒ H.C.F. = 4. Or 8 = 2 × 2 × 2 : 12 = 2 × 2 × 3 : 20 = 2 × 2 × 5 : ⇒ H. C. F = 2 × 2 = 4 Blunders (−3) B1 An inapplicable element of U. [But see S1]. B2 A listing of elements of U with 4 included. B3 Correct factors of 8 or12 or 20 but no conclusion drawn re H.C.F. Slips (−1) S1 1 or 2 as H.C.F. Misreadings (−1) M1 L.C.M. given i.e. 120. Attempts (2 marks) A1 Incorrect factors of 8 and/or 10 and/or 20 e.g. 8 = 2 × 3. Worthless (0) W1 Any number ∉ U except 120. [See M1]. W2 A listing of elements of U with 4 not included. Part (c) (i) 5 marks M is the set of natural numbers from 1 to 20, inclusive. (i) List the elements of M that are multiples of 3. (i) 3, 6, 9, 12, 15, 18. Slips (−1) S1 Each correct element omitted and/or each incorrect element included. Worthless (0) W1 No applicable multiple of 3 appears. Page 4 of 37 Att 2 Part (c) (ii) 5 marks M is the set of natural numbers from 1 to 20, inclusive. (ii) List the elements of M that are multiples of 5. Att 2 (ii) 5, 10, 15, 20. Slips (−1) S1 Each correct element omitted and/or each incorrect element included. Worthless (0) W1 No applicable multiple of 5 appears. Part (c) (iii) (iii) 5 marks Att 2 Write down the lowest common multiple of 3 and 5. 15 (iii) 3, 6, 9, 12, 15, 18. * * 5, 10, 15, 20. Or 3 × 5 = 15 Accept candidate’s least common number from their incorrect answers in parts (i) and (ii) for full marks. Accept an indication of candidate’s L.C.M. for full marks. Blunders (−3) B1 An inapplicable multiple of 3 only and/or an inapplicable multiple of 5 only. Misreadings (−1) M1 H.C.F = 1. Worthless (0) W1 Numbers other than multiples of 3 or 5 (But see 1st *) Page 5 of 37 Part (c) (iv) (iv) (iv) * 5 marks Att 2 Express 10 as the sum of three prime numbers 10 = 2 + 3 + 5. Accept a listing of 2, 3, 5 for full marks. Blunders (−3) B1 Each correct prime constituent omitted and/or each incorrect constituent included. Attempts (2 marks) A1 Some attempt at product e.g. 1 × 2 × 5. (But see W1) Worthless (0) W1 No applicable prime number appears i.e. 2 or 3 or 5 do not appear. Page 6 of 37 QUESTION 2 Part (a) Part (b) Part (c) 10 marks 20 (5, 10, 5) marks 20 (5, 5, 10) marks Att 3 Att (2,3,2) Att (2,2,3) Part (a) 10 marks Att 3 If 12 m2 of carpet cost €504, find the cost of 15 m2 of the same carpet. (a) 12 m 2 ≡ 504 504 = 42 12 ⇒ 15m 2 ≡ 42 × 15 = 630 ⇒ 1m 2 ≡ * Correct answer without work ⇒ 7 marks. 12 * 15 × 504 = 403 ⋅ 2 ⇒ 7 marks (B1). 4 * 5 × 504 = 403 ⋅ 2 ⇒ 7 marks (B1). 5 * Indicates 15 12 or 4 only and stops. ⇒ 4 marks. (No use of 504 (−3) and possible Slips (−3)). 504 504 * 12 or 12 = 42 and stops ⇒ 4 marks (No use of 15 (−3) and possible Slips (−3)). * 504 × 15 or 504 × 15 = 7560 ⇒ 4 marks. * Incorrect answer without work ⇒ 0 marks. Blunders (−3) 12 4 B1 × 504 or × 504 and continues. [ 403 ⋅ 20 as answer.] 15 5 B2 Divisor ≠ 12 and continues. [But see B1] B3 Incorrect multiplier i.e. ≠ 15 and continues. [But see B1] B4 Divisor ≠ 4 and continues. [But see B1] B5 Incorrect multiplier i.e. ≠ 5 and continues. [But see B1] B6 15 : 12 = 504 : x and continues. B7 Error in decimal point. Slips (−1) S1 Numerical errors (max –3). Attempts (3 marks) 504 A1 Divisor ≠ 12 or ≠ 4 e.g. 504 15 or 5 and stops. 4 A2 Indicates 12 15 or 5 or12: 15 or 504: x only and stops. A3 6048 only.i.e. multiplies 504 by 12. 1 A4 12 only appears Worthless (0) W1 504 + 15 = 519. Page 7 of 37 Part (b) (i) 5 marks Att 2 a9 × a5 (i) Simplify 6 , giving your answer in the form a n , where n ∈ N. 2 a ×a (i) a 9 × a 5 a 14 = 8 = a6 . a6 × a2 a a×a×a×a×a×a×a×a×a×a×a×a×a×a = a × a × a × a × a × a = a6. a×a×a×a×a×a×a×a * * * * a 14 and stops ⇒ 2 marks. a8 a 14 and stops ⇒ 2 marks. a 3 × a 3 and stops ⇒ 2 marks. Correct answer without work ⇒ 2 marks. Blunders (−3) B1 Each error in calculation involving indices. B2 Each incorrect number of a’s in the extended form. B3 Each incorrect elimination in the extended form. B4 a 3 × a 3 as an answer. Slips (−1) a 14 a 14 1 S1 = 6 or = −6 as final answers. 8 8 a a a S2 a × a × a × a × a × a as answer. Attempts (2 marks) A1 Some manipulation of indices e.g. a 9 × a 5 = a 45 only. Page 8 of 37 Part (b) (ii) Estimate 10 marks Att 3 By rounding each of these numbers to the nearest whole number, estimate 56 ⋅ 214 the value of . 2 ⋅ 31 + 5 ⋅ 79 (ii) (ii) 56 ⋅ 214 is approximately equal to: 2 ⋅ 31 + 5 ⋅ 79 56 56 = = 2 * * + 7 8 6 56 and stops ⇒ 4 marks. 2+6 No penalty if the intermediate step between approximations and final answer not shown 56 e.g. not shown. 8 Blunders (−3) B1 Error in rounding off to the nearest whole number (each time). B2 Decimal point error in calculation of approximate value. B3 An arithmetical operation other than indicated. 56 56 + and continues. B4 2 6 56 B5 + 6 = 28 + 6 = 34 . 2 Slips (−1) S1 Numerical errors in arithmetical operations. Attempts (3 marks) A1 Only one or two approximations made to the given numbers. Worthless (0) W1 No approximations made to given numbers. Page 9 of 37 Part (b) (iii) Calculator (iii) 5 marks Using a calculator, or otherwise, find the exact value of (iii) 56 ⋅ 214 = 6 ⋅ 94 8 ⋅1 Blunders (−3) B1 Otherwise: Error(s) in decimal point. 56 ⋅ 214 56 ⋅ 214 B2 Otherwise: + = 24.335 + 9.709 = 34 ⋅ 044 . 2 ⋅ 31 5 ⋅ 79 56 ⋅ 214 + 5 ⋅ 79 = 30 ⋅ 12506494. B3 Otherwise: 2 ⋅ 31 B4 Calculator: Incorrect Answer. Slips (−1) S1 Otherwise: numerical errors in addition or division. (max −3). Attempts (2 marks) A1 Some correct calculation done. Page 10 of 37 Att 2 56 ⋅ 214 . 2 ⋅ 31 + 5 ⋅ 79 Part (c) (i) (i) 5 marks Att 2 Using a calculator, or otherwise, find the exact value of: 49 1 2 (i) 7 Blunders (−3) 1 2 1 2 1 2 1 2 1 2 1 2 B1 Mishandles 49 e.g. 49 = 2401 , 49 = 24 ⋅ 5 , 49 = 49 ⋅ 5 , 49 = 98 , 49 = B2 Calculator: Incorrect Answer. B3 Otherwise: error in use of Maths. Tables e.g. 2 ⋅ 214 (wrong page). Misreadings (−1) 1 1 1 M1 49 2 = 2 = = 0 ⋅ 0004164 . 2401 49 99 2 . 1 2 M2 49 = 3 49 = 3 ⋅ 6593. Attempts (2 marks) A1 is mentioned. Part (c) (ii) (ii) (ii) 5 marks Using a calculator, or otherwise, find the exact value of Att 2 1 . 6⋅4 1 = 0 ⋅ 15625 6⋅4 Blunders (−3) 1 B1 = 6 ⋅ 4 = 2 ⋅ 529 or (6 ⋅ 4) 2 = 40 ⋅ 96 . 6⋅4 1 B2 6 ⋅ 4 × 1 = 6 ⋅ 4 or . 24 B3 Calculator: Incorrect Answer. B4 Otherwise: Decimal point error in division or in use of Maths. Tables e.g. Slips (−1) S1 Otherwise: numerical errors (max. of −3). S2 Maths. Tables: 0 ⋅ 1563 . S3 Rounded off to 0 ⋅ 2, 0 ⋅ 16, 0 ⋅ 156, 0 ⋅ 1563. S4 Incorrectly rounded off e.g. 0 ⋅ 1562, also attracts S3. Attempts (2 marks) A1 Some correct calculation done. 1 10 5 A2 = or = and stops. 6 ⋅ 4 64 32 Page 11 of 37 1 = 1563 . 6⋅4 Part (c) (iii) (iii) (iii) * * B4 B5 B6 Att 3 Using a calculator, or otherwise, evaluate 3 ⋅ 14 65 ⋅ 61 × − (2 ⋅ 42) 2 . 0 ⋅ 47 Give your answer correct to two decimal places. 8 ⋅ 1 × 6 ⋅ 6808511 − 5.8564 (3 marks) = 54 ⋅ 114894 − 5 ⋅ 8564 (6 marks) = 48 ⋅ 258494 (9 marks) = 48 ⋅ 26. (10 marks) Correct answer without work ⇒ 7 marks. Correct answer (without work) incorrectly rounded off ⇒ 6 marks.(See 1st * and S3). Blunders (−3) B1 Mishandles B2 B3 10 marks 65 ⋅ 61 e.g. (65 ⋅ 61) 2 = 4304 ⋅ 6721. Mishandles (2 ⋅ 42) 2 e.g. 2 ⋅ 42 × 2 = 4 ⋅ 84. An arithmetical operation other than a given one e.g. + for × . 65 ⋅ 61 × 3 ⋅ 14 − (2 ⋅ 42) 2 = 41 ⋅ 65 (breaking order). [Check candidate’s calculations] 0 ⋅ 47 3 ⋅ 14 65 ⋅ 61 − (2 ⋅ 42) 2 × = 14 ⋅ 99 (breaking order). [Check candidate’s calculations] 0 ⋅ 47 Error in decimal point. Slips (−1) S1 Numerical errors in arithmetical operations (to max−3). S2 Each rounding off which would affect the final rounded off answer (max −3). [Check candidate’s calculations] S3 Fails to round off or incorrectly rounds off when giving final answer. Attempts (3 marks) A1 Calculator: incorrect answer without work. A2 65 ⋅ 61 = 8 ⋅ 1 and stops. 3 ⋅ 14 A3 = 6 ⋅ 680851064 and stops. 0 ⋅ 47 A4 65 ⋅ 61 × 3 ⋅ 14 = 25 ⋅ 434 and stops. A5 (2 ⋅ 42) 2 = 5 ⋅ 8564 and stops. Page 12 of 37 QUESTION 3 Part (a) Part (b) Part (c) 10 marks 20 (10, 10) marks 20 (10, 10) marks Part (a) 10 marks (a) Att 3 Aoife bought 3 compact discs at € 16 ⋅ 50 each and 2 magazines at € 4 ⋅ 20 each. How much did she pay altogether? (a) 16 ⋅ 50 × 3 = 49 ⋅ 50 or 4 ⋅ 20 × 2 = 8 ⋅ 40 ⇒ total cost : 49 ⋅ 50 + 8 ⋅ 40 = 57 ⋅ 90. * * * * * Att 3 Att (3, 3) Att (3, 3) 16 ⋅ 50 + 16 ⋅ 50 + 16 ⋅ 50 = 49 ⋅ 50. 4 ⋅ 20 + 4 ⋅ 20 = 8 ⋅ 40 ⇒ total cost : 49 ⋅ 50 + 8 ⋅ 40 = 57 ⋅ 90. Accept 5790, 57 ⋅ 90 or 57 ⋅ 9 regardless of subsequent labelling or work. Final addition step subject to maximum deduction of −3. Adds 16 ⋅ 50 to 4 ⋅ 20 = 20 ⋅ 70 and stops ⇒ 3 marks. [Oversimplification]. Correct answer without work ⇒ 7 marks. Incorrect answer without work ⇒ 0 marks. Blunders (−3) B1 Each missing product when finding items cost e.g. 16 ⋅ 50 not multiplied by 3. B2 Incorrect number of additions when finding items cost e.g. 16 ⋅ 50 + 16 ⋅ 50 only. B3 Fails to find total cost i.e. no addition. B4 49 ⋅ 50 − 8 ⋅ 40 = 41 ⋅ 10 . B5 Error in decimal point. Slips (−1) S1 Numerical errors (to max –3). Page 13 of 37 Part (b) (i) (i) (i) 10(5, 5) marks Att (2,2) Patrick bought a car for €14 080 and sold it for €16 000. Calculate his profit as a percentage of the selling price. Profit: €16 000− €14 080 = €1920 Percentage of the selling price: 1920 × 100 = 12% 16000 Profit: (5 marks) * Correct answer without work ⇒ 2 marks. * Incorrect answer without work ⇒ 0 marks. 16000 + 100 = 8 ⋅ 3 + 100 = 108 ⋅ 3 ⇒ 2 marks. * 1920 Blunders (−3) B1 Adds €14 080 to €16 000. Slips (−1) S1 Numerical errors in arithmetical operations. Attempts (2 marks) A1 Some indication of subtraction. Percentage of selling price: (5 marks) Blunders (−3) B1 As percentage of cost price. 16000 × 100 = 833 ⋅ 3 . 1920 B2 Mishandles the calculation of profit as a percentage e.g. B3 B4 Error in decimal point. Illegal cancellation(s) in correct method of calculation of profit as a percentage. Slips (−1) S1 Numerical errors in arithmetical operations. (to a max −3). Attempts (2 marks) A1 Some use of 100 or of the given data or the calculated profit. A2 " Profit" " Selling Price " or " Profit" " Selling Price "×100 and stops i.e. no substitution of values. Page 14 of 37 Part (b) (ii) 10 marks Att 3 €6000 is invested at 5% per annum. What is the amount of the investment at the end of one year? (ii) 1% = 60 5% = 300 Amount = €6300 P × T × R 6000 × 1 × 5 = = 300 100 100 Amount = €6300 I= 6000 × 1 ⋅ 05 = 6300 Amount = €6300 6000 @ or + 5% = 300 (use of % button, calculator)⇒ €6300 as total. * * * * * €300 (with work shown) and stops ⇒ 7 marks. 6000 × 5 = 30000 and stops ⇒ 4 marks (B1 + B3). 6000 × 5 = 30000 + 6000 = 36000 ⇒ 7 marks (B1). Correct answer without work ⇒ 7 marks. Incorrect answer without work ⇒ 0 marks. Blunders (−3) B1 Mishandles 5%, e.g. 6000 × 5 or 6000 ÷ 5 (6000 must be used). B2 Error in decimal point (once only). B3 Stops at interest i.e. fails to calculate amount. B4 Subtracts to calculate amount. B5 Incorrect substitution into formula and continues. [say T = 2: but 6000 must be used ]. 6000 × 1 × 5 B6 Illegal cancellation(s) in . 100 B7 6000 × ⋅05 = 300 and stops. B8 1 ⋅ 05 = 1 ⋅ 5. Slips (−1) S1 Numerical errors in arithmetical operations. (to a max −3) Attempts (3 marks) A1 correct formula with or without substitution and stops. A2 some use of 100 in attempt to find percentage e.g. 5% = Page 15 of 37 5 and stops. 100 3(c) 20(5, 5, 5, 5) marks Att (2, 2, 2, 2) Helen’s weekly wage is €850. She pays income tax at the rate of 20% on the first €600 of her wage and income tax at the rate of 42% on the remainder of her wage. Helen has a weekly tax credit of €54. Part (c) (i) 5 marks Att 2 Calculate the tax payable at the rate of 20% on the first €600 of her wage. (i) 1% = 6 20% = 120 Tax = €120. Tax = 600 × 20 = €120 100 600 × 0 ⋅ 2 = €120. . Correct answer without work ⇒ 2 marks. Incorrect answer without work ⇒ 0 marks. * * Blunders (−3) B1 Mishandles 20%, e.g. 600 × 20 = 12 000 or 600 ÷ 20 = 30. B2 Uses €850 instead of €600. B3 Error in decimal point. B4 Illegal cancellation(s) in correct method of calculation of tax. Slips (−1) S1 Numerical errors in arithmetical operations. (to a max −3) Attempts (2 marks) 20 and stops. A1 Some use of 100 in attempt to find percentage e.g. 20% = 100 Part (c) (ii) (ii) 5 marks Att 2 Calculate the tax payable at the rate of 42% on the remainder of her wage. (ii) 1% = 2 ⋅ 5 42% = 105 Tax = €105 Remainder of wage = €850 − €600 = €250 Tax = 250 × 42 = €105 100 250 × 0 ⋅ 42 = €105 Blunders (−3) B1 Mishandles 42%, e.g. 250 × 42 or 250 ÷ 42 . (But no penalty if the error is as in Part (c) (i)). B2 Uses €850 or €600 instead of €250. B3 Error in decimal point. B4 Illegal cancellation(s) in correct method of calculation of tax. Slips (−1) S1 Numerical errors in arithmetical operations. (to a max −3). Attempts (2 marks) 42 A1 Some use of 100 in attempt to find percentage e.g. 42% = 100 and stops. Page 16 of 37 Part (c) (iii) 5 marks Hence calculate Helen’s gross tax. (iii) Helen’s gross tax = €120 + €105 = €225 (iii) * * Att 2 Incorrect answer without work ⇒ 0 marks. Allow candidate’s incorrect answers from parts (i) and (ii). Blunders (−3) B1 €120 − €105 = €15. B2 Misuse of tax credit. Slips (−1) S1 Numerical errors in arithmetical operations. (to a max −3). Part (c) (iv) (iv) (iv) * * * * 5 marks Calculate the tax payable by Helen. Tax payable = €225 − €54 = €171 No use of tax credit ⇒ 0 marks. Incorrect answer without work ⇒ 0 marks. Allow candidate’s incorrect gross tax figure from Part (iii). 171 only ⇒ 2 marks. Blunders (−3) B1 Misuse of tax credit e.g. 225 + 54 = 279. Slips (−1) S1 Numerical errors in arithmetical operations. (to a max −3) Page 17 of 37 Att 2 QUESTION 4 Part (a) Part (b) Part (c) 10(5, 5) marks 20(10, 10) marks 20(5, 5, 5, 5) marks Part (a) (i) * * * 5 marks (i) If x = 4, find the value of: 5 x + 3 (i) 5 x + 3 = 5(4) + 3 = 20 + 3 = 23 20 + 3 ⇒ 4 marks. Correct answer without work ⇒ 2 marks. Incorrect answer without work ⇒ 0 marks. Blunders (−3) B1 Incorrect numerical substitution for x and continues. B2 Leaves 5(4) in the answer. B3 Breaks order i.e. [ 5(4 + 3) = 35 ]. B4 5(4) taken as 54 . Slips (−1) S1 Numerical errors.( to a max −3). Attempts (2 marks) A1 Substitution and stops e.g. 5(4) only. Worthless (0) W1 Incorrect substitution for x and stops. Page 18 of 37 Att (2, 2) Att (3, 3) Att (2, 2, 2, 2) Att 2 Part (a) (ii) 5 marks (ii) If x = 4, find the value of: x 2 − x + 7 x 2 − x + 7 = ( 4) 2 − 4 + 7 (ii) = 16 − 4 + 7 = 19 * * * * * 16 – 4 + 7 ⇒ 3 marks. 16 – 4 + 7 = 16 − 11 = 5 ⇒ 4 marks. 12 + 7 ⇒ 4 marks. Correct answer without work ⇒ 2 marks. Incorrect answer without work ⇒ 0 marks. Blunders (−3) B1 Incorrect numerical substitution for x and continues. B2 Mishandles (4) 2 i.e. (4) 2 = 8 or leaves (4) 2 in answer. B3 Mishandles − (4) i.e. = 4 . B4 Breaks order i.e. [ 16 − 1(4) = 15(4) = 60 ]. B5 − 1(4) taken as − 1 + 4 . B6 −1(4) clearly taken as −14. Slips (−1) S1 Numerical errors (to max –3). Attempts (2 marks) A1 Substitution and stops i.e. (4) 2 − (4) + 7 only. A2 Incomplete substitution and continues or stops. A3 4x substituted for x in both terms with x and continues or stops. Page 19 of 37 Att 2 Part (b) (i) (i) (i) 10 marks Att 3 Multiply (3 x − 2) by (4 x + 5) and write your answer in its simplest form. (3 x − 2)(4 x + 5) = 3 x(4 x + 5) − 2(4 x + 5) = 12 x 2 + 15 x − 8 x − 10 = 12 x 2 + 7 x − 10. * * Correct answer without work ⇒ 7 marks. Incorrect answer without work ⇒ 0 marks. Blunders (−3) B1 Each incorrect term or each term omitted on multiplication. Slips (−1) S1 Each incorrect term or each term omitted in final simplification. (to a max of −3) Attempts (3 marks) A1 Any correct multiplication. A2 3 x(4 x + 5) − 2(4 x + 5) and stops. A3 4 x(3 x − 2) + 5(3 x − 2) and stops. Worthless (0) W1 (3 x − 2) ± (4 x + 5) stops or continues. W2 Adding unlike terms before attempt at multiplication. Page 20 of 37 Part (b) (ii) 10 marks (ii) Att 3 Write in its simplest form (4 x 2 − 3 x + 7) + ( x 2 − 2 x − 8) (ii) ( 4 x 2 − 3 x + 7 ) + ( x 2 − 2 x − 8) = 4 x 2 − 3x + 7 + x 2 − 2 x − 8 = 5x 2 − 5x − 1 * * Stops after correct removal of brackets ⇒ 7 marks. Incorrect answer without work ⇒ 0 marks. Blunders (−3) B1 Each incorrect term or each term omitted on bracket removal. Slips (−1) S1 Each incorrect term or each term omitted in final simplification.(max −3) Misreadings (-1) M1 (4 x 2 − 3x + 7) × ( x 2 − 2 x − 8) . Apply B1 as each incorrect term or each term omitted on multiplication. Attempts (3 marks) A1 Any correct addition of a pair of like terms. A2 (4 x 2 − 3x + 7) = 4 x 2 − 3 x + 7 only or ( x 2 − 2 x − 8) = x 2 − 2 x − 8 only. A3 Treats as equation e.g. 4 x 2 − x 2 − 3 x + 2 x + 7 + 8 . Worthless (0) W1 Adding unlike terms before removal of brackets. Page 21 of 37 Part (c) 20 (5, 5, 5, 5) marks A rectangle has a length ( x + 6) cm and width x cm, as in the diagram Part (c) (i) x+6 x 5 marks Att 2 Find the perimeter of this rectangle in terms of x. (i) Att (2, 2, 2, 2) (i) x + x + ( x + 6) + ( x + 6) 2( x + x + 6) 4 x + 12 * * * * * * Accept either x + x + ( x + 6) + ( x + 6) or 2( x + x + 6) for full marks. If x + x + ( x + 6) + ( x + 6) present give full marks for this section, irrespective of any subsequent errors within the section. Brackets as above not required, accept x + x + x + 6 + x + 6. Incorrect answer without work ⇒ 0 marks. 4 x + 12 only ⇒ 2 marks. 4 x + 12 and diagram as in Att 2 ⇒ 5 marks. Blunders (−3) B1 Adding only any two of the four sides required e.g. x + ( x + 6) . B2 x × ( x + 6) or x × x or ( x + 6) × ( x + 6) . B3 x + x + ( x + 6) . B4 x + ( x + 6) + ( x + 6) . Slips (−1) S1 Numerical errors. (max −3) Attempts (2 marks) A1 P = 2( L + B ) or P = ( L + B ) . A2 Diagram as over: Worthless (0) W1 x only or x + 6 only. x+6 x x x+6 Page 22 of 37 Part (c) (ii) (ii) * Att 2 If the perimeter of the rectangle is 40 cm, write down an equation in x to represent this information. . (ii) * * 5 marks 4 x + 12 = 40. Accept either x + x + ( x + 6) + ( x + 6) = 40 or 2( x + x + 6) or 4 x + 12 = 40 for full marks. If x + x + ( x + 6) + ( x + 6) = 40 present give full marks for this section, irrespective of any subsequent errors within the section. Accept candidate’s incorrect perimeter from (c) (i) = 40 for full marks. Blunders (−3) B1 x × ( x + 6) = 40 [if not the candidate’s expression above]. Slips (−1) S1 An x or an x + 6 omitted in transcription from part (c) (i). ( max −3) Part (c) (iii) 5 marks (iii) (iii) Att 2 Solve the equation that you formed in part (ii) above, for x. x + x + ( x + 6) + ( x + 6) = 40 4 x + 12 = 40 4 x + 12 = 40 4 x = 40 − 12 4 x = 28 4 x = 40 − 12 4 x = 28 x=7 x=7 x + x + x + x = 40 − 6 − 6 4x = 28 x=7 Candidate’s equation from (ii) must be progressed to the form " ax = ....." before any marks can be earned for this section. * x = 284 ⇒ 4 marks. * Correct Equation for part (ii) may be embedded in this section and would earn full marks for part (ii) if part (ii) is incorrect or vacant. * Correct answer without work ⇒ 2 marks. * Incorrect answer without work ⇒ 0 marks. Blunders (−3) B1 Error(s) in progressing equation (e.g. transposition). B2 Adds ‘x s to ‘numbers’ and continues e.g. 4 x + 12 = 16x. * Slips (−1) S1 Errors in addition (to max −3). S2 Error in division e.g. x = 284 ⇒ x = 6 (say). 28 S3 4 and stops. Attempts (2 marks) A1 x + x + x + x = 40 − 6 − 6 and stops. A2 4x only or 12 only appears and stops. A3 Correct answer from arithmetical approach. Page 23 of 37 Part (c) (iv) 5 marks (iv) Find the area of the square with the same perimeter as the given rectangle. Give your answer in cm2. Perimeter of Square = 4l (iv) 4l = 40 l = 10 l cm * * ⇒ Area of square = 10 × 10 = 100 cm 2 . Accept 100 as answer (no need for units). Correct answer without work ⇒ 2 marks. Blunders (−3) l ≠ 10 and continues. B1 Slips (−1) S1 Numerical errors within correct approach (max−3). Attempts (2 marks) x + x + ( x + 6) + ( x + 6) 4 x + 12 A1 or and stops. 4 4 A2 Some use of 40 e.g. (40) 2 or 40 . Worthless (0) W1 7 × 13 or 7 × 13 = 91. Page 24 of 37 Att 2 QUESTION 5 Part (a) Part (b) Part (c) 10 marks 20 (5, 5, 5, 5) marks 20 (5, 5, 10) marks Part (a) Att 3 Att (2, 2, 2, 2) Att (2, 2, 3) 10 marks Att 3 Solve the equation 5 x − 6 = 3( x + 4) 5 x − 6 = 3 x + 12 (a) 5 x − 3 x = 12 + 6 (4 marks) 2 x = 18 (7 marks) x=9 * * * (3 marks) (10 marks) x = 182 ⇒ 9 marks. Correct answer without work ⇒ 7 marks. Incorrect answer without work ⇒ 0 marks. Blunders (−3) B1 Error in distributive law and continues, e.g. 3x + 4 or x + 12 (once only). B2 Each error in progressing equation (e.g. transposition). Slips (−1) S1 Error in division e.g. x = 182 ⇒ x = 8 (say). S2 Numerical errors (to max −3). 18 S3 2 and stops. Attempts (3 marks) A1 Adds or subtracts‘x’s to ‘numbers’ and continues e.g. 5x − 6 = ± x or 3( x + 4) = 3(5 x) = 15 x. A2 5 x − 6 = 3 x + 12 and stops. A3 3x appears and stops. A4 5 x = 3( x + 4) + 6 and stops. Worthless (0) W1 Adds or subtracts‘x’s to ‘numbers’ and stops. Page 25 of 37 Part (b) (i) (i) 5 marks Factorise Att 2 4ab + 8b 4b(a + 2) (i) * Accept 4(ab + 2b) or b(4a + 8) or 2(2ab + 4b) for 5 marks. Blunders (−3) B1 An incorrect common factor. B2 Stops after some correct effort at factorisation e.g. 4b(a ) + 4b(2) or similar. Slips (−1) S1 Numerical errors when taking out a factor e.g. 4b(a + 4) . Attempts (2 marks) A1 4(ab) and /or + 8(b) or effort at brackets. A2 Indication of common factor e.g. 4ab + 8b . Part (b) (ii) (ii) * * 5 marks Factorise: ab + 2ac + 5b + 10c ab + 2ac + 5b + 10c (ii) Att 2 ab + 5b + 2ac + 10c a (b + 2c) + 5(b + 2c) (b + 2c)(a + 5) b(a + 5) + 2c(a + 5) (a + 5)(b + 2c) Correct answer without work ⇒ 2 marks. Incorrect answer without work ⇒ 0 marks. Blunders (−3) B1 Stops after first line of correct factorisation. B2 Error(s) in factorising any pair of terms. B3 Incorrect common factor and continues e.g. a (b + 2c) + 5(b + c) = (b + 2c)(a + 5) . An instance of correct answer from incorrect work. Slips (−1) S1 (b + 2c) ± (a + 5) . S2 Correct second line of factorisation but gives 5a (b + 2c). Attempts (2 marks) A1 Pairing off, or indication of pairing off, and stops. A2 Correctly factorises any pair and stops. Page 26 of 37 Part (b) (iii) (iii) 5 marks Att 2 Factorise: x 2 + 2 x − 15 (iii) x 2 + 2 x − 15 = x 2 + 5 x − 3x − 15 = x( x + 5) − 3( x + 5) (2 marks) = ( x + 5)( x − 3) x +5 x (2 marks) * * * * ⇒ ( x + 5)( x − 3) −3 Quadratic equation formula method is subject to Slips and Blunders. Accept (with or without brackets) for 5 marks any of the following (x + 5) and (x − 3) . ( The word and is written down.) (x + 5) or (x − 3) . ( The word or is written down.) Accept ( x + 5), ( x − 3) for 5 marks. Correct answer without work ⇒ 5 marks. Blunders (−3) B1 Incorrect two term linear factors of x 2 + 2 x − 15 formed from correct, but not applicable, factors of x 2 and ± 15 . B2 Correct cross method but factors not written. B3 x( x + 5) − 3( x + 5) or x( x − 3) + 5( x − 3) and stops. B4 Incorrect common factor and continues (applies to guide number method). Slips (−1) S1 Uses quadratic equation formula, but has wrong signs in factors (once only). S2 Uses quadratic equation formula to find x = −5 and x = 3 and stops. S3 ( x + 5) ± ( x − 3) . Attempts (2 marks) A1 Correct factors of x 2 only. A2 Correct factors of –15 or +15 only. A3 5 x − 3 x only appears. A4 Correct quadratic equation formula with or without substitution and stops. Page 27 of 37 Part (b) (iv) (iv) (iv) * * 5 marks Att 2 Factorise: x 2 − y 2 ( x + y )( x − y ) Accept (with or without brackets) for 5 marks any of the following (x + y ) and (x − y ) . [The word and is written down.] (x + y ) or (x − y ) . [The word or is written down.] Accept ( x + y ), ( x − y ) for 5 marks. Blunders (−3) B1 Incorrect two term linear factors of x 2 − y 2 formed from correct, but not applicable, factor of x 2 and ± y 2 . B2 ( y + x)( y − x) . Slips (−1) S1 Solves x 2 = y 2 to give x = y and x = − y and stops. S2 ( x + y) ± ( x − y) . Attempts (2 marks) A1 Correct factors of x 2 only. A2 Correct factors of y 2 or − y 2 only. A3 x or ± y appears. A4 x 2 − y 2 = x.x − y. y and stops. A5 ( xy )( xy ). A6 Mention of the difference of two squares. Page 28 of 37 Part (c) (i) (i) (i) * * * * * * 5 marks Att 2 x+5 x+2 + as a single fraction. 4 3 Give your answer in its simplest form. Express 3( x + 5) + 4( x + 2) 12 3x + 15 + 4 x + 8 = 12 7 x + 23 = 12 (5 marks) x + 5 x + 2 2x + 7 + = ⇒ 0 marks. 4 3 7 All Blunders and Slips in the simplification of the numerator subject to a max. deduction (−3). 3( x + 5) + 4( x + 2) and stops ⇒ 2 marks. (B3) 12 3 x + 15 + 4 x + 8 and stops ⇒ 4 marks. (S3) 12 14 x + 46 ⇒ 4 marks. (S3) 24 14 x + 46 ⇒ 3 marks. (S1and S3) Adds numerators and then denominators i.e. Blunders (−3) B1 Incorrect common denominator and continues. B2 Incorrect numerator from candidate’s common denominator. e.g. B3 B4 B5 No simplification of numerator. Errors in distributive law. [See * 2] Errors in sign when multiplying. [See * 2] Slips (−1) S1 Correct common denominator implied. S2 Numerical errors in arithmetical operations. S3 Not in simplest form. [See * 4]. Attempts (2 marks) A1 12 only or a multiple of 12 only appears. 5 x 2 x 15 x + 8 x A2 + = . 4 3 12 Worthless (0) x + 5 x + 2 W1 and stops. 4 3 6 x 3x x + 5 x + 2 5x 2x 7 x W2 + and stops or + = + = = x. 4 3 4 3 4 3 7 Page 29 of 37 4( x + 5) + 3( x + 2) . 12 Part (c) (ii) 5 marks Att 2 Hence, or otherwise, solve the equation (ii) x+5 x+2 5 + = 4 3 2 (ii) 7 x + 23 5 = 12 2 14 x + 46 = 60 14 x = 60 − 46 14 x = 14 x = 1. * * * * * * * 7 x + 23 5 − =0 12 2 2(7 x + 23) − 12(5) =0 12 14 x + 46 − 60 = 0 14 x − 14 = 0 14 x = 14 x =1 12(7 x + 23) 12(5) = 12 2 7 x + 23 = 6(5) 7 x + 23 = 30 7x = 7 x =1 Candidate’s equation must be of the form 3( x + 5) + 4( x + 2) = 30 12 3 x + 15 + 4 x + 8 = 30 7 x + 23 = 30 7 x = 30 − 23 7x = 7 x =1 ax + b 5 = if full marks are to be earned for this c 2 section. Correct trial and error ⇒ Att mark only. x + 5 x + 2 5x 2x 7 x 7x 5 5 + = + = = x from (i) and then = or x = ⇒ 2 marks. 4 3 4 3 7 7 2 2 5 x 2 x 15 x + 8 x 15 x + 8 x 5 23 x 5 + = from (i) and then = or = ⇒ 2 marks. 4 3 12 12 2 12 2 x + 5 x + 2 2x + 7 2x + 7 5 + = from (i) and then = etc can gain full marks. 4 3 7 7 2 x+5 x+2 5 + = ⇒ 4 x + 20 + 3 x + 6 = 10 etc ⇒ B2. 4 3 2 x+5 x+2 5 + = ⇒ x + 1 ⋅ 25 + x + 0 ⋅ 66 = 2 ⋅ 5 etc ⇒ B2. 4 3 2 Blunders (−3) B1 Error(s) in establishing an equation without fractions and continues. B2 Error(s) in progressing equation (e.g. transposition). Slips (−1) S1 Error in division in final step to find x. Attempts (2 marks) A1 Adding unlike terms in progressing equation. A2 Some effort at removal of fractions. A3 Oversimplification e.g. 7 x + 23 = 5 and continues. A4 Oversimplification as a result of errors in part (i). A5 Trial and error. Page 30 of 37 Part (c) (iii) (iii) 10 marks Att 3 Solve for x and for y: 3x − y = 8 x + 2y = 5 (iii) 3x − y = 8 x + 2y = 5 3x − y = 8 x + 2y = 5 y = 3x − 8 x + 2(3x − 8) = 5 6 x − 2 y = 16 3x − y = 8 3 x + 6 y = 15 x + 6 x − 16 = 5 7 x = 5 + 16 − 7 y = −7 y =1 x=3 7 x = 21 x=3 x + 2y = 5 7 x = 21 x=3 y =1 * * y =1 Apply only one blunder deduction (B1 or B2) to any error(s) in establishing the first equation in terms of x only or the first equation in terms of y only. Finding the second variable is subject to a maximum deduction (−3). Blunders (−3) B1 Error(s) in establishing the first equation in terms of x only [ 7 x = 21 ] or the first equation in terms of y only [ − 7 y = −7 ] through elimination by cancellation. B2 Error(s) in establishing the first equation in terms of x only or the first equation in terms of y only through elimination by substitution. B3 Errors in transposition in solving the first one variable equation. B4 Errors in transposition when finding second variable. B5 Incorrect substitution when finding second variable. B6 Finds one variable only. Slips (−1) S1 Numerical errors (max −3) in solving first one variable equation and when finding second variable. Attempts (3 marks) A1 Attempt at transposition and stops. A2 Multiplies either equation by some number and stops. A3 Correct answers without algebraic work. Page 31 of 37 QUESTION 6 Part (a) Part (b) Part (c) 10 (5, 5) marks 30 (20, 10) marks 10 (5, 5) marks Part (a) (i) 5 marks (i) f ( x ) = 5 x − 6. (i) * * * * Att 2 Find: f (3) f (3) = 5(3) − 6 = 15 − 6 =9 * Att (2,2) Att (7,3) Att (2,2) (4 marks) (5 marks) Function concept correct: f (3) = 5(3) − 6 or f (2) = 15 − 6 i.e. multiplication of 3 by 5 is clearly indicated or is implied by subsequent work. Completion of f (3) subject to maximum deduction of –1. Correct function concept i.e. 5(3) − 6 and stops ⇒ 4 marks. Ignores x giving 5−6 = −1 ⇒ 0 marks. 3[ f ( x)] = 15 x − 18 ⇒ 0 marks. Correct answer without work ⇒ 2 marks. Blunders (−3) B1 f (3) incorrect: misunderstanding of the concept of a function. Misreadings (−1) M1 f (−3) instead of f (3). Slips (−1) S1 Numerical errors (to max –1). Attempts (2 marks) A1 Treats as equation and continues or stops. Page 32 of 37 Part (a) (ii) (ii) 5 marks f ( x ) = 5 x − 6. (ii) Att 2 f (−2) f (−2) = 5(−2) − 6 = −10 − 6 = −16 * * * * * (5 marks) Function concept correct: f (−2) = 5(−2) − 6 or f (−2) = −10 − 6 i.e. multiplication of −2 by 5 is clearly indicated or is implied by subsequent work. Completion of f (−2) subject to maximum deduction of –1. Correct function concept i.e. 5(−2) − 6 and stops ⇒ 4 marks. Ignores x giving 5−6 = −1 ⇒ 0 marks. − 2[ f ( x)] = −10 x + 12 ⇒ 0 marks. Correct answer without work ⇒ 2 marks. Blunders (−3) B1 f (−2) incorrect: misunderstanding of the concept of a function. Misreadings (−1) M1 f (2) instead of f (−2). Slips (−1) S1 Numerical errors and sign errors (to max –1). Attempts (2 marks) A1 Treats as equation and continues or stops. Page 33 of 37 Part (b) 20 marks Att 7 Draw the graph of the function f : x → x2 + x − 3 in the domain −3 ≤ x ≤ 2, f (-3) f (-2) f (-1) f (0) f(1) f(2) = = = = = = where x ∈ R. (-3)2 + (-3) −3 = 3 (-2)2 + (-2) −3 = −1 (-1)2 + (-1) −3 = −3 (0)2 + (0) − 3 = −3 (1)2 + (1) − 3 = −1 (2)2 + (2) − 3 = 3 or x x2 x -3 f(x) -3 9 -3 -3 3 -2 4 -2 -3 −1 -1 1 -1 -3 -3 0 0 0 -3 -3 1 1 1 -3 -1 2 4 2 -3 3 Table 20 marks Att 7 * Each individual error in the rows other than the f(x) row, apart from Blunders below, attracts a deduction of −1 subject to a maximum deduction of −3 per row. [f(x) max(−6)] Blunders (−3) x 2 taken as 2x all the way. [In row headed x 2 by candidate] B1 B2 x taken as −x all the way. [In row headed x by candidate] B3 -3 calculated as –3x all the way. [In row headed − 3 by candidate] B4 Adds in top row when evaluating f (x) . B5 Omits ‘−3’ row or omits ‘x’ row. B6 Omits a value in the domain each time to max of −9 (5 values missing ⇒ Att 7). B7 Each incorrect image without work. Slips (−1) S1 Numerical Slips (to max −3) in any row other than f (x) row. S2 Misreads ‘−3’ as ‘+3’ and places ‘+3’ in the table or ‘+x’ as ‘−x’ and places ‘−x’ in the table. S3 Each incorrect f (x) value calculated by addition within columns in student’s table (no limit). But note B4. Attempts (7 marks) A1 Omits x 2 row from table or treats x 2 as x. A2 Table with only f (x) = x2. A3 Any effort at calculating point(s). A4 One point only calculated and nothing else. Page 34 of 37 Graph * * * 10 Marks Att 3 Att 7 + Att 3 ⇒ one point only calculated and graphed correctly. Correct graph but no table ⇒ full marks, i.e. 30 marks. Accept reversed co-ordinates (i) if axes not labelled or (ii) if axes are reversed to compensate (see B1 below). Blunders (−3) B1 Reversed co-ordinates plotted against non-reversed axes (once only) [See 3rd *]. B2 Axes not graduated uniformly (once only). B3 Points not joined or joined in incorrect order (once only). Slips (−1) S1 Each point of candidate graphed incorrectly. S2 Each point from table not graphed (subject to N1). Attempts (3 marks) A1 Graduated axes only (need not be labelled). Page 35 of 37 Part (c) (i) 5 marks Att 2 Use the graph drawn in 6(b) to estimate: (i) the values of x for which f ( x) = 0. (i) Work to be shown on graph and answers written here. x = −2 ⋅ 3 or x = 1 ⋅ 3 * * Correct answer (clearly consistent with graph) inside tolerance without graphical indication ⇒ 2 marks. A candidate’s incorrect graph can earn up to full marks for this section. [Use similar tolerances] Blunders (−3) B1 Answer on diagram but outside of tolerance ( ± 0 ⋅ 25 ). B2 Fails to write down the answers. B3 Only one answer or indication. Attempts (2 marks) A1 Algebraic evaluation. Worthless (0) W1 Answers outside of tolerance without graphical indication. W2 f (0) giving −3 as answer. Page 36 of 37 Part (c) (ii) 5 marks Att 2 Use the graph drawn in 6(b) to estimate: (ii) the value of f ( x) when x = 0 ⋅ 5. (ii) Work to be shown on graph and answers written here f (0 ⋅ 5) = −2 ⋅ 25 * * Correct answer (clearly consistent with graph) inside tolerance without graphical indication ⇒ 2 marks. A candidate’s incorrect graph can earn up to full marks for this section. (Use similar tolerances) Blunders (−3) B1 Answer on diagram but outside of tolerance ( ± 0 ⋅ 25 ). B2 Fails to write down the answer. Attempts (2 marks) A1 Algebraic evaluation or calculator. Worthless (0) W1 Answer outside of tolerance without graphical indication. Page 37 of 37