Ripdos, Eul Mark T. BSEE 3-9 16.1) Which one of the following is not an irrational number? A. sqrt of 2 B. sq rt of 4 C. sq rt of 3 D. sqrt of 5 The irrational number is a number that cannot 𝑎 be expressed as a simple fraction (ex., 𝑏 ). The choices √2 , √3 , 𝑎𝑛𝑑 √5 are irrational number except for √4 = 2 , 𝑤ℎ𝑒𝑟𝑒 2 can be 2 expressed into fraction ( ). 1 16.2) At what distance from the 250-pound weight and a 300-pound weight balance when placed on each end of an 11-foot bar? A. 4 ft B. 5 ft C. 6 ft D. 7 ft 250𝑑1 = 3300 − 300𝑑1 Let 𝑑1 = Distance 1 300𝑑1 + 250𝑑1 = 3300 𝑑2 = Distance 2 550𝑑1 = 3300 𝑑2 = 11 − 𝑑1 250𝑑1 = 300𝑑2 𝑑1 = 250𝑑1 = 300(11 − 𝑑1 ) 𝑑1= 5ft 41.1) Given the function, f(x) = x² + 2x, find f(f(3)). A. 15 B. 225 C.255 𝑓(3) = (3)2 + 2(3) = 15 𝑓(15) = (15)2 + 2(5) = 255 3300 550 D. 275 41.2) Find the sum of 10 terms of the arithmetic progression 2, 5, 8... A. 140 B. 188 C. 155 𝑟 = 5−2=3 D. 220 𝑆= 𝑎𝑛 = 𝑎1 + (𝑛 − 1)(𝑟) (𝑎1 + 𝑎𝑛 )𝑛 2 𝑆= 𝑎10 = 2 + (10 − 1)(3) (2+29)10 2 = 155 = 29 66.1) Peter and John working together can finish painting a house in 6 days. Peter working alone can finish it in 5 days less than John. How long will it take Peter to finish the work alone? A. 15 days B. 18 days C. 12 days D. 10 days 6𝑥 + 30 + 6𝑥 = 𝑥 2 + 5𝑥 Let: Peter 2 𝑥 = 7𝑥 + 30 𝑥 2 = 12𝑥 + 30 − 5𝑥 =x 𝑥 2 = 7𝑥 + 30 John = x+5 (𝑥 − 10)(𝑥 + 3) = 0 6 6 + =1 𝑥 𝑥+5 𝑥 = 10 𝑑𝑎𝑦𝑠 6𝑥 + 30 + 6𝑥 = 𝑥 2 + 5𝑥 𝑥 2 = 12𝑥 + 30 − 5𝑥 66.2) Find the sum of three arithmetic means between 1 and 9. 𝑥 2 = 7𝑥 + 30 A. 15 B. 16 C. 13 𝑆= (𝑎1 + 𝑎𝑛 )𝑛 2 𝑆= (9 + 1)(3) 2 𝑆 = 15 D. 14 91.1) If 10𝑘 = 1/2 what is the value of 10k + 3? A. 400 B. 200 10𝑘 = 1 2 C. 300 D. 500 10k + 3 =? 1 𝑘 × 𝑙𝑛(10) = ln ( ) 2 𝑘= ln(0.5) ln (10) 𝑘 = −0.3010299957 10k + 3 = 500 91.2) A farmer bought 20 chickens consisting of roosters, hens and chicks for $20. Each rooster cost $3 each, each hen at $1.50 each and each chick at $0.50 each. How many chicks did he buy? A. 11 B.13 C. 12 D. 14 𝑅 = $3, 𝐻 = $1.2, 𝐶 = $0.5 1.5(18 − 𝐶) + 0.5𝐶 = 14 Assume he only bought two roasters total cost of $6 𝐶 = 13 𝐻 + 𝐶 = 18 1.5𝐻 + 0.5𝐶 = 14 116.1) A three-person maintenance crew could clean a certain building in 4 hours, whereas a four-person crew could do the job in 3 hours. If one worker of the four-person crew was an hour late, how long did the job take? A. 3.25 hrs. B. 4.55 hrs. C. 2.2h hrs. D 3.55 hrs. Considering that 1 person from the 4-person crew is late by 1 hour, the work is done for 1 hr. by a 3-person crew. the 3-person crew completes 100% of the job in 4 hrs., hence, in 1 hr. it completes 25 % of the job. Now when 75% of the job is unfinished, the 4th member joins, so now it is a 4-person crew to do 75% of the job. If they can complete 100% job in 3hrs, they would complete the 75% job in 2.25 hrs. 75×3 . 100 Hence total time required for completion of the job = 2.25 + 1= 3.25 hrs. 116.2) The 1st term of an arithmetic sequence is -15 and the 5th term is 13. Find the 40th term. A. 258 B. 245 𝑑= C. 188 13 − (−15) 4 D. 196 𝑎𝑛 = 𝑎1 + (𝑛 − 1)𝑑 𝑎40 = −15 + (−1)7 𝑑=7 𝑎40 =285 141.1) John and Peter are linemen. John can string 10 miles of line in 3 days, while together they can string it in 1 day. How long in days would it take Peter alone to string the same line? A. 1 1/2 days B. 1 4/5 days C. 2 days D. 2 3/4 days 1 1 + =1 3 𝑋 𝑥 + 3 = 3𝑥 𝑥= 3 1 = 1.5 𝑜𝑟 1 𝑑𝑎𝑦𝑠 2 2 141.2) A ball is dropped from a height of 100 ft. On each rebound, the ball rises to one half of the height from which it last fell. Find the total distance the ball has traveled, up to the instant it hits the ground for the 12th time. s time t is 5 hours After the w in A. 290 ft B. 280 ft 𝑠= 𝑠= 𝑎1 (1 − 𝑟 2 ) , 1−𝑟 1 2 100 (1 − (2) ) 1 1 − (2) C. 270 ft 𝑟= D. 300 ft 1 2 = 150 𝑠 = 150𝑥2 = 300𝑓𝑡 166.1) Simplify: A. x + y 𝑥 −1 +𝑦 −1 𝑥 −1 𝑦 −1 B. x-y C. x/y D. 2xy 𝑥 −1 + 𝑦 −1 𝑥 −1 𝑦 −1 1 1 1 1 𝑥𝑦 𝑥𝑦 𝑥+𝑦 = = ( + ) 𝑥𝑦 = + 11 𝑥 𝑦 𝑥 𝑦 𝑥𝑦 = 𝑦+𝑥 166.2) Jonathan has $1 and 15 cents worth of change in his pocket. He has three more dimes than quarters and two more dimes than nickels. How many quarters he has? A. 2 B. 4 C. 3 D. 5 Q= quarters, D = dimes, N = nickels 0.4𝑄 = 1.15 − 0.35 0.25𝑄 + 0.05𝐷 + 0.1𝑁 = 1.15 𝑄=2 𝐷 = 𝑄 + 3, 𝐷 = 𝑁+2 Therefore, 𝑁 = 𝑄 + 1 0.25𝑄 + 0.05(𝑄 + 3) + 0.1( 𝑄 + 1 ) = 1.15 191.1) Find the numerical value of the Roman numeral MMDCCCLIX. A. 2859 B. 2649 C. 2354 D. 2599 M=1000, D=500, C=100, L=50, X=10, I=1 2000 +500+300+50+10-1= 2859 191.2) A and B start at the same time from two places 136 km apart and travel toward each other. A travel 10 kph and B at 8 kph. If B rests 1 hour on the way, in how many hours will they meet? A. 10 hours B. 8 hours C. 7 hours 10𝑥 + 8 (𝑥 − 1) = 136 10𝑥 + 8𝑥 = 136 + 8 18𝑥 = 144 𝑥=8 D. 9 hour 216.1) There are three consecutive integers. The sum of the smallest and largest is 36. Find the largest number. A. 16 B. 18 C. 17 D. 19 By trial and error let z = highest integer and x = lowest integer Let’s assume that the numbers are 17, 18, 19 Z=19 and x =17 , 19 + 17 = 36 , therefore 19 is the highest integer 216.2) Find the 37th term of an AP if the 4th term is 6 and common difference is 5. A. 172 B. 174 C. 171 D. 173 𝑎1 = 64 − 53 − 52 − 51 = −91 𝑎𝑛 = 𝑎1 + (𝑛 − 1)(𝑑) 𝑎37 = −9 + (37 − 1)(5) 𝑎37 = 171 241.1) One student can solve a math problem in 6 minutes. Another student can solve a math problem in 5 minutes. How long can they solve 110 problems? A. 300 minutes B. 270 minutes 𝑠1 = 1 , 6 𝑠2 = C. 330 minutes 1 5 1 1 𝑡 + 𝑡 = 110 6 5 11 𝑡 = 110 , 30 𝑡 = 300 𝑚𝑖𝑛𝑢𝑡𝑒𝑠 D. 240 minutes 241.2) A box contains beetles (with 6 legs) spiders (with 8 legs), and centipedes (with 100 legs). The box contains 78 heads, 1656 legs and 6 more spiders than twice the number of centipedes, how many beetles are there in the box? A. 30 B. 36 C. 27 D. 12 𝑙𝑒𝑡; 𝑥 = 𝑏𝑒𝑒𝑡𝑙𝑒𝑠, 𝑦 = 𝑠𝑝𝑖𝑑𝑒𝑟𝑠 , 𝑧 = 𝑐𝑒𝑛𝑡𝑖𝑝𝑒𝑑𝑒𝑠 𝑒𝑞1 . 6𝑥 + 8𝑦 + 100𝑧 = 1656 And, 𝑒𝑞2 . 𝑥 + 𝑦 + 𝑧 = 100 𝑥 + (6 + 2𝑧) + 𝑧 = 100 𝑒𝑞3 . 𝑦 = 6 + 2𝑧 𝑥 + 3𝑧 = 72 Substituting equations we get, Solving these two equations 𝑥 + 3𝑧 = 72 6𝑥 + 8(6 + 2𝑧) + 100𝑧 = 1656 6𝑥 + 16𝑧 + 100𝑧 = 1656 − 48 6𝑥 + 116𝑧 = 1608 And 6𝑥 + 116𝑧 = 1608 we get z= 12 and x =36 beetles