Exemplar Questions Mathematics EOYE 2022 Class 8 Topic: Introduction to Set Theory 1. If S = {1, 2, 3} are the elements of set S then; A. 1 belongs to set S B. 3 does not belong to set S C. 2 does not belong to set S (1 mark) Solution: A [1 belongs to set S] 1, 2 and 3 are the elements of set S and therefore A is the correct answer. The statements in options B and C are false. 2. Write down the elements of the following descriptive set in numerical form: (1 mark) a) set of all integers between 10 and 15 Solution: {11, 12, 13, 14} Integers between 10 and 15 are: 11, 12, 13 and 14. 3. 30 students were asked if they had a bicycle (B), a mobile phone (M) and a computer (C). The results are shown in the Venn diagram: a) Find the value of x (1 mark) b) Shade M ∩ C on the Venn Diagram below: (1 mark) c) Shade B U C on the Venn Diagram below: (1 mark) d) List the number of students who own a bicycle, a mobile phone and a computer (1 mark) Solution: a) Total number of students = 30 X = 30 – [2 + 4 + 1 + 7 + 6 + 3 + 2] = 30 – 25 X=5 b) M ∩ C Intersection of sets is the set of elements, which are common to both the given sets. In set theory, for any two sets A and B, the intersection is defined as the set of all the elements in set A that are also present in set B. We use the symbol '∩' that denotes 'intersection of' The overlapping region of two circles represents the intersection of the two sets. Therefore, the overlapping region of circles M and C represents the intersection of the M and C c) B U C The union of two sets A and B is defined as the set of all the elements, which lie in set A and set B, or both the elements in A and B altogether. The union of the set is denoted by the symbol '∪'. The entire region of two circles represents the union of the two sets. Therefore, the entire region of circles B and C represents the union of the B and C d) 7 students The number of students who own a bicycle, a mobile phone and a computer is indicated by the shaded region in the Venn diagram below: Therefore, the respective number of students are 7 Topic: Graphical Representation of Simultaneous Linear Inequalities 1. The graph below represents which of the following linear inequality: A. Y < 3 B. Y > 3 C. Y ≥ 3 (1 mark) Solution: B [Y > 3] The area above the line Y = 3 is shaded in the graph above. In addition, because the line is dotted, it means that the line Y = 3 is not included in the shaded region. Therefore, the shaded region represents the inequality Y > 3 2. Shade the region satisfies x ≤ -1 in the graph below: (2 marks) Solution: The shaded region on the graph below indicates the inequality x ≤ -1 All of the area to the left of the line x = -1 is to be shaded. In addition to this, the line x = -1 has to be solid because it is included in the shaded region. [1 mark for shading the correct region. 1 mark for making the line x = -1 solid] Topic: Area and Volume (Last 3 ATs) 1. The volume of this rectangular prism is: A. 24 cm3 B. 60 cm C. 20 cm3 D. 240 cm3 (1 mark) Solution: D [240 cm3] Volume of rectangular prism or cuboid = L x W x H = 10 x 6 x 4 = 240 cm3 2. The volume of a cube of length 4 cm is: A. 8 cm3 B. 64 cm3 C. 36 cm3 D. 16 cm3 (1 mark) Solution: B [64 cm3] Volume of cube = L x L x L = 4 x 4 x 4 = 64 cm3 3. The height and radius of a closed cylinder are 23 cm and 5 cm. Find its volume and total surface area. (6 marks) Solution: (2 marks for correct volume formula and entering values correctly. 1 mark for correct volume answer) (2 marks for correct surface area formula and entering values correctly. 1 mark for correct surface area answer) Volume of cylinder = πr2h= 3.142 x 52 x 23 = 1806.65 cm3 Total Surface Area of cylinder = 2πrh + 2πr2 = (2 x 3.142 x 5 x 23) + (2 x 3.142 x 52) = 879.76 cm2 4. Find the surface area of the given cuboid. (3 marks) Solution: (2 marks for correct formula and entering values correctly. 1 mark for correct answer) Surface area of cuboid = 2(L x W) + 2(L x H) + 2(W x H) = 2(7 x 4) + 2(7 x 3) + 2(4 x 3) = 122 cm2 5. Calculate the area of the shaded region (5 marks) Solution: (2 marks for correctly calculating the area of triangle. 2 marks for correctly calculating the area of circle. 1 mark for correctly calculating the area of the shaded region) Area of Circle = π r2 = 3.142 x 22 = 12.57 m2 Area of Triangle = ½ x b x h = ½ x 6 x 6 = 18 m2 Area of shaded region = 18 – 12.57 = 5.43 m2 6. Calculate the perimeter of the given shape: (5 marks) Solution: (1 mark for correctly calculating the value of the unknown side. 3 marks for correctly adding the lengths of all sides to find the total perimeter) Length of unknown side = 12 – 3 – 3 = 6 cm Perimeter of the given shape = 10 + 12 + 10 + 3 + 8 + 3 + 8 + 6 = 60 cm 7. Find the volume of the given triangular prism (3 marks) Solution: (2 marks for correct formula and entering values correctly. 1 mark for correct answer) 1 Volume of triangular prism = (𝑡𝑟𝑖𝑎𝑛𝑔𝑢𝑙𝑎𝑟 𝑏𝑎𝑠𝑒 𝑎𝑟𝑒𝑎)(ℎ𝑒𝑖𝑔ℎ𝑡) = (2 𝑥 3 𝑥 4) (15) = 90 cm3 8. Find the perimeter of the following semi-circle: (Take π = 3.142) (3 marks) Solution: (2 marks for correct formula and entering values correctly. 1 mark for correct answer) Perimeter of semi-circle = (𝐶𝑖𝑟𝑐𝑢𝑚𝑓𝑒𝑟𝑒𝑛𝑐𝑒 𝑜𝑓 𝑠𝑒𝑚𝑖 − 𝑐𝑖𝑟𝑐𝑙𝑒) + (𝑑𝑖𝑎𝑚𝑒𝑡𝑒𝑟 𝑜𝑓 𝑠𝑒𝑚𝑖 − 𝑐𝑖𝑟𝑐𝑙𝑒) 1 = (2 𝑥 2 𝑥 𝜋 𝑥 𝑟) + (10) 1 = (2 𝑥 2 𝑥 3.142 𝑥 5) + (10) = (15.71) + (10) = 25.71 𝑐𝑚 Topic: Probability 1. Write down the sample space when a six-sided dice is rolled (3 marks) Solution: (1 mark for two correct numbers. For example, if a writes 2 and 3 only, he/she will get 1 mark. If a student writes 3, 4 and 5, he/she will get 1.5 marks. If a student writes 1, 2, 3, 4, 5 and 6, he/she will get full marks) Sample Space - A sample space is a collection or a set of ALL possible outcomes of an experiment Therefore, the sample space for the roll of a six-sided die is: 1, 2, 3, 4, 5 and 6 2. A fair six-sided die is rolled once. Find the probability of: (6 marks – 2 marks each) a) Getting a 4 b) Getting an even number c) Getting a prime number Solution: a) 1/6 The sample space for the roll of a six-sided die is: 1, 2, 3, 4, 5 and 6 Number of all Possible outcomes is 6 Number of Target outcomes is 1 (The number: 4) 𝐍𝐮𝐦𝐛𝐞𝐫 𝐨𝐟 𝐓𝐚𝐫𝐠𝐞𝐭 𝐨𝐮𝐭𝐜𝐨𝐦𝐞 So, Probability of getting a 4 is: 𝐍𝐮𝐦𝐛𝐞𝐫 𝐨𝐟 𝐚𝐥𝐥 𝐏𝐨𝐬𝐬𝐢𝐛𝐥𝐞 𝐨𝐮𝐭𝐜𝐨𝐦𝐞𝐬 = 1/6 [1 mark to be deducted if either of number of favorable outcomes or number of all possible outcomes is incorrect] b) 3/6 or ½ The sample space for the roll of a six-sided die is: 1, 2, 3, 4, 5 and 6 Number of all Possible outcomes is 6 Number of Target outcomes is 3 (Even numbers: 2, 4 and 6) 𝐍𝐮𝐦𝐛𝐞𝐫 𝐨𝐟 𝐓𝐚𝐫𝐠𝐞𝐭 𝐨𝐮𝐭𝐜𝐨𝐦𝐞 So, Probability of getting an even number is: 𝐍𝐮𝐦𝐛𝐞𝐫 𝐨𝐟 𝐚𝐥𝐥 𝐏𝐨𝐬𝐬𝐢𝐛𝐥𝐞 𝐨𝐮𝐭𝐜𝐨𝐦𝐞𝐬 = 3/6 = ½ [1 mark to be deducted if either of number of favorable outcomes or number of all possible outcomes is incorrect] c) 3/6 or ½ The sample space for the roll of a six-sided die is: 1, 2, 3, 4, 5 and 6 Number of all Possible outcomes is 6 Number of Target outcomes is 3 (Prime numbers: 2, 3 and 5) 𝐍𝐮𝐦𝐛𝐞𝐫 𝐨𝐟 𝐓𝐚𝐫𝐠𝐞𝐭 𝐨𝐮𝐭𝐜𝐨𝐦𝐞 So, Probability of getting a prime number is: 𝐍𝐮𝐦𝐛𝐞𝐫 𝐨𝐟 𝐚𝐥𝐥 𝐏𝐨𝐬𝐬𝐢𝐛𝐥𝐞 𝐨𝐮𝐭𝐜𝐨𝐦𝐞𝐬 = 3/6 = ½ [1 mark to be deducted if either of number of favorable outcomes or number of all possible outcomes is incorrect] Topic: Coordinate Geometry 1. Find the gradient and the y-intercept of the line given by the following equation: (2 marks) 𝑦 = 3 − 2𝑥 Solution: In the equation y = mx + c the value of m is called the slope, (or gradient), of the line and the value of c is called the y-intercept of the line So, re-arranging the above equation in the standard form: 𝑦 = −2𝑥 + 3 m = -2 (Gradient) c = 3 (y-intercept) 2. A is the point with coordinates (4, 11). B is the point with coordinates (8, 3). a) Work out the coordinates of the midpoint of AB. (3 marks) b) Calculate the gradient of the line AB (3 marks) Solution: a) Mid-point is of a line can be calculated by using the formula below: 𝑀= 𝑀= 𝑥1 + 𝑥2 𝑦1 + 𝑦2 + 2 2 4 + 8 11 + 3 + 2 2 𝑀= 12 14 + 2 2 𝑴 = (𝟔, 𝟕) (2 marks for correct formula and entering values correctly. 1 mark for correct answer) b) Gradient of a line can be calculated by using the formula below: 𝑚= 𝑚= 𝑦2 − 𝑦1 𝑥2 − 𝑥2 3 − 11 8−4 𝑚= −8 4 𝒎 = −𝟐 (2 marks for correct formula and entering values correctly. 1 mark for correct answer) Topic: Transformation 1. Draw the reflection of Polygons in the given line, on the graphs below: a) X-axis (3 marks) b) Y-axis (3 marks) Solution: a) When you reflect a point across the x-axis, the x-coordinate remains the same, but the sign of the y-coordinate reverses. The reflection of point (x, y) across the x-axis is (x, -y). (1 mark for each of the three points correctly reflected) b) When you reflect a point across the y-axis, the y-coordinate remains the same, but the sign of the x-coordinate reverses. The reflection of point (x, y) across the x-axis is (-x, y). The point at the y-axis remains the same when reflected across y-axis (1 mark for each of the three points correctly reflected)