JAMB Mathematics 2002 past questions and answers

49 questions. Try each one, then open the answer to check yourself and read the explanation.

Question 1

Indices

Without using tables, evaluate (343)1/3 × (0.14)−1 × (25)−1/2

  1. A.10
  2. B.12
  3. C.8
  4. D.7
Show the answer and explanation

Answer: A (10)

Explanation

(343)1/3 = 7, (0.14)−1 = 100/14 and (25)−1/2 = 1/5. So 7 × 100/14 × 1/5 = 50/5 = 10.

Open this question

Question 2

Sets

In a school, 220 students offer Biology or Mathematics or both. 125 offer Biology and 110 Mathematics. How many offer Biology but not Mathematics?

  1. A.95
  2. B.80
  3. C.125
  4. D.110
Show the answer and explanation

Answer: D (110)

Explanation

Both = 125 + 110 − 220 = 15. Biology but not Mathematics = 125 − 15 = 110.

Open this question

Question 3

Fractions, Decimals and Approximation

Simplify 52.4 − 5.7 − 3.45 − 1.75

  1. A.41.4
  2. B.41.5
  3. C.42.1
  4. D.42.2
Show the answer and explanation

Answer: B (41.5)

Explanation

Add the amounts being subtracted: 5.7 + 3.45 + 1.75 = 10.9. Then 52.4 − 10.9 = 41.5.

Open this question

Question 4

Surds

Simplify (√0.7 + √70)2

  1. A.84.7
  2. B.70.7
  3. C.217.7
  4. D.168.7
Show the answer and explanation

Answer: A (84.7)

Explanation

Expand: 0.7 + 70 + 2√(0.7 × 70) = 70.7 + 2√49 = 70.7 + 14 = 84.7.

Open this question

Question 5

Fractions, Decimals and Approximation

Evaluate (0.21 × 0.072 × 0.00054)/(0.006 × 1.68 × 0.063), correct to four significant figures.

  1. A.0.01286
  2. B.0.01285
  3. C.0.1286
  4. D.0.1285
Show the answer and explanation

Answer: A (0.01286)

Explanation

The numerator is 0.0000081648 and the denominator 0.00063504. Their quotient is 0.012857…, which is 0.01286 to 4 significant figures.

Open this question

Question 6

Commercial Arithmetic

A trader bought goats for N4000 each. He sold them for N180,000 at a loss of 25%. How many goats did he buy?

  1. A.60
  2. B.50
  3. C.45
  4. D.36
Show the answer and explanation

Answer: A (60)

Explanation

Selling at a 25% loss means N180 000 is 75% of the cost, so the cost was N240 000. At N4000 each, that is 60 goats.

Open this question

Question 7

Integration

If dy/dx = 2x − 3 and y = 3 when x = 0, find y in terms of x.

  1. A.2x2 − 3x
  2. B.x2 − 3x
  3. C.x2 − 3x − 3
  4. D.x2 − 3x + 3
Show the answer and explanation

Answer: D (x2 − 3x + 3)

Explanation

Integrating gives y = x2 − 3x + k. Since y = 3 when x = 0, k = 3.

Open this question

Question 8

Differentiation

Find the derivative of y = sin2(5x) with respect to x.

  1. A.10 sin 5x cos 5x
  2. B.5 sin 5x cos 5x
  3. C.2 sin 5x cos 5x
  4. D.15 sin 5x cos 5x
Show the answer and explanation

Answer: A (10 sin 5x cos 5x)

Explanation

By the chain rule: 2 sin 5x × cos 5x × 5 = 10 sin 5x cos 5x.

Open this question

Question 9

Differentiation

The slope of the tangent to the curve y = 3x2 − 2x + 5 at the point (1, 6) is

  1. A.4
  2. B.1
  3. C.6
  4. D.5
Show the answer and explanation

Answer: A (4)

Explanation

dy/dx = 6x − 2, which is 6 − 2 = 4 at x = 1.

Open this question

Question 10

Integration

Evaluate ∫sin 3x dx

  1. A.(2/3)cos 3x + c
  2. B.(1/3)cos 3x + c
  3. C.−(1/3)cos 3x + c
  4. D.−(2/3)cos 3x + c
Show the answer and explanation

Answer: C (−(1/3)cos 3x + c)

Explanation

The integral of sin ax is −(1/a)cos ax. With a = 3 this is −(1/3)cos 3x + c.

Open this question

Question 11

Differentiation

A circle with a radius 5cm has its radius increasing at the rate of 0.2cms−1. What will be the corresponding increase in the area?

  1. A.2π
  2. B.5π
  3. C.π
  4. D.4π
Show the answer and explanation

Answer: A (2π)

Explanation

A = πr2, so dA/dt = 2πr × dr/dt = 2π × 5 × 0.2 = 2π cm2 per second.

Open this question

Question 12

Differentiation

If y = x2 − 1/x, find dy/dx

  1. A.2x − 1/x2
  2. B.2x + x2
  3. C.2x − x2
  4. D.2x + 1/x2
Show the answer and explanation

Answer: D (2x + 1/x2)

Explanation

−1/x = −x−1, whose derivative is +x−2. So dy/dx = 2x + 1/x2.

Open this question

Question 13

Inequalities

Use the graph above to find the values of p and q if px + qy ≤ 4.

Diagram for this question
  1. A.p = 2, q = 1
  2. B.p = 2, q = −1
  3. C.p = 1, q = 2
  4. D.p = −1, q = 2
Show the answer and explanation

Answer: D (p = −1, q = 2)

Explanation

The boundary passes through (−4, 0) and (0, 2), so it is y = x/2 + 2, i.e. −x + 2y = 4. The shaded side is below the line, so −x + 2y ≤ 4, giving p = −1, q = 2.

Open this question

Question 14

Polynomials

Solve for x in the equation x3 − 5x2 − x + 5 = 0

  1. A.1, −1 or 5
  2. B.1, 1 or −5
  3. C.−1, 1 or −5
  4. D.1, 1 or 5
Show the answer and explanation

Answer: A (1, −1 or 5)

Explanation

Group the terms: x2(x − 5) − 1(x − 5) = (x − 5)(x − 1)(x + 1) = 0. So x = 1, −1 or 5.

Open this question

Question 15

Variation

The time taken to do a piece of work is inversely proportional to the number of men employed. If it takes 45 men to do a piece of work in 5 days, how long will it take 25 men?

  1. A.15 days
  2. B.12 days
  3. C.5 days
  4. D.9 days
Show the answer and explanation

Answer: D (9 days)

Explanation

The work needs 45 × 5 = 225 man-days. With 25 men it takes 225 ÷ 25 = 9 days.

Open this question

Question 16

Matrices and Determinants

If P = [2, 1; −3, 0] and I is a 2 × 2 unit matrix, evaluate P2 − 2P + 4I

  1. A.[9, 4; −12, 1]
  2. B.[−3, 0; 0, −3]
  3. C.[1, 0; 0, 1]
  4. D.[1, 4; 4, 1]
Show the answer and explanation

Answer: C ([1, 0; 0, 1])

Explanation

P2 = [1, 2; −6, −3] and 2P = [4, 2; −6, 0]. So P2 − 2P + 4I = [1 − 4 + 4, 0; 0, −3 + 4] = [1, 0; 0, 1].

Open this question

Question 17

Inequalities

Find the range of values of x for which (x + 2)/4 − (2x − 3)/3 < 4

  1. A.x > −6
  2. B.x > −3
  3. C.x < 8
  4. D.x < 4
Show the answer and explanation

Answer: A (x > −6)

Explanation

Multiply by 12: 3x + 6 − 8x + 12 < 48, so −5x < 30. Dividing by −5 reverses the sign: x > −6.

Open this question

Question 18

Differentiation

Find the maximum value of y in the equation y = 1 − 2x − 3x2

  1. A.5/4
  2. B.5/3
  3. C.3/4
  4. D.4/3
Show the answer and explanation

Answer: D (4/3)

Explanation

dy/dx = −2 − 6x = 0 gives x = −1/3. Then y = 1 + 2/3 − 1/3 = 4/3.

Open this question

Question 19

Progressions

If the 9th term of an A.P. is five times the 5th term, find the relationship between a and d.

  1. A.2a + d = 0
  2. B.3a + 5d = 0
  3. C.a + 3d = 0
  4. D.a + 2d = 0
Show the answer and explanation

Answer: C (a + 3d = 0)

Explanation

a + 8d = 5(a + 4d) gives a + 8d = 5a + 20d, so 4a + 12d = 0, i.e. a + 3d = 0.

Open this question

Question 21

Algebraic Expressions

The inverse of the function f(x) = 3x + 4 is

  1. A.(1/3)(x − 4)
  2. B.(1/5)(x − 5)
  3. C.(1/4)(x + 3)
  4. D.(1/3)(x + 4)
Show the answer and explanation

Answer: A ((1/3)(x − 4))

Explanation

Put y = 3x + 4 and solve for x: x = (y − 4)/3. So f−1(x) = (1/3)(x − 4).

Open this question

Question 22

Linear and Simultaneous Equations

If −2 is the solution of the equation 2x + 1 − 3c = 2c + 3x − 7, find the value of c.

  1. A.4
  2. B.3
  3. C.2
  4. D.1
Show the answer and explanation

Answer: C (2)

Explanation

Put x = −2: −4 + 1 − 3c = 2c − 6 − 7, so −3 − 3c = 2c − 13. Then 10 = 5c and c = 2.

Open this question

Question 23

Binary Operations

An operation * is defined on the set of integers p and q by p * q = pq + p + q. Find 2 * (3 * 4).

  1. A.59
  2. B.19
  3. C.67
  4. D.38
Show the answer and explanation

Answer: A (59)

Explanation

First 3 * 4 = 12 + 3 + 4 = 19. Then 2 * 19 = 38 + 2 + 19 = 59.

Open this question

Question 24

Matrices and Determinants

If N = [3, 5, −4; 6, −3, −5; −2, 2, 1], find |N|

  1. A.17
  2. B.23
  3. C.65
  4. D.91
Show the answer and explanation

Answer: A (17)

Explanation

Expanding along the first row: 3(−3 + 10) − 5(6 − 10) + (−4)(12 − 6) = 21 + 20 − 24 = 17.

Open this question

Question 25

Progressions

The sum to infinity of the series 1 + 1/3 + 1/9 + 1/27 + … is

  1. A.11/3
  2. B.10/3
  3. C.5/2
  4. D.3/2
Show the answer and explanation

Answer: D (3/2)

Explanation

This is a G.P. with a = 1 and r = 1/3. Its sum to infinity is a/(1 − r) = 1 ÷ (2/3) = 3/2.

Open this question

Question 26

Variation

If x varies directly as √n and x = 9 when n = 9, find x when n = 17/9

  1. A.4
  2. B.27
  3. C.√3
  4. D.√17
Show the answer and explanation

Answer: D (√17)

Explanation

x = k√n with 9 = 3k, so k = 3. When n = 17/9, x = 3 × √17/3 = √17.

Open this question

Question 27

Angles and Polygons

In the diagram above, PST is a straight line, PQ = QS = RS. If ∠RST = 72°, find x.

Diagram for this question
  1. A.36°
  2. B.18°
  3. C.72°
  4. D.24°
Show the answer and explanation

Answer: D (24°)

Explanation

Triangle PQS is isosceles, so ∠QSP = x and the exterior angle ∠SQR = 2x. Triangle QSR is isosceles, so ∠SRQ = 2x. ∠RST is exterior to triangle PRS, so 3x = 72° and x = 24°.

Open this question

Question 28

Mensuration of Plane Shapes

A chord of a circle subtends an angle of 120° at the centre of a circle of diameter 4√3cm. Calculate the area of the major sector.

  1. A.4πcm2
  2. B.32πcm2
  3. C.16πcm2
  4. D.8πcm2
Show the answer and explanation

Answer: D (8πcm2)

Explanation

The radius is 2√3 cm, so r2 = 12. The major sector has angle 360° − 120° = 240°, giving area (240/360) × π × 12 = 8π cm2.

Open this question

Question 29

Loci

Find the equation of the set of points which are equidistant from the parallel lines x = 1 and x = 7

  1. A.y = 3
  2. B.x = 3
  3. C.x = 4
  4. D.y = 4
Show the answer and explanation

Answer: C (x = 4)

Explanation

Points halfway between the vertical lines x = 1 and x = 7 lie on the vertical line x = (1 + 7)/2 = 4.

Open this question

Question 30

Mensuration of Plane Shapes

In the diagram above, XZ is the diameter of the circle XYZW, with centre O and radius 15/2cm. If XY = 12cm, find the area of the triangle XYZ.

Diagram for this question
  1. A.54cm2
  2. B.45cm2
  3. C.27cm2
  4. D.75cm2
Show the answer and explanation

Answer: A (54cm2)

Explanation

The angle in a semicircle is 90°, so ∠XYZ = 90° and XZ = 15 cm. Then YZ = √(225 − 144) = 9 cm, and the area is ½ × 12 × 9 = 54 cm2.

Open this question

Question 31

Trigonometry

If tan θ = 4/3, calculate sin2θ − cos2θ.

  1. A.16/25
  2. B.24/25
  3. C.7/25
  4. D.9/25
Show the answer and explanation

Answer: C (7/25)

Explanation

A 3-4-5 triangle gives sin θ = 4/5 and cos θ = 3/5. So sin2θ − cos2θ = 16/25 − 9/25 = 7/25.

Open this question

Question 32

Mensuration of Plane Shapes

In the diagram above are two concentric circles of radii r and R respectively with centre O. If r = (2/5)R, express the area of the shaded portion in terms of π and R.

Diagram for this question
  1. A.(21/25)πR2
  2. B.(9/25)πR2
  3. C.(21/23)πR2
  4. D.(5/9)πR2
Show the answer and explanation

Answer: A ((21/25)πR2)

Explanation

The shaded ring has area πR2 − πr2 = πR2 − (4/25)πR2 = (21/25)πR2.

Open this question

Question 33

Mensuration of Solids

A bucket is 12cm in diameter at the top, 8cm in diameter at the bottom and 4cm deep. Calculate its volume.

  1. A.(304/3)πcm3
  2. B.144πcm3
  3. C.(128/3)πcm3
  4. D.72πcm3
Show the answer and explanation

Answer: A ((304/3)πcm3)

Explanation

The bucket is a frustum with radii 6 and 4 and height 4. V = (πh/3)(R2 + Rr + r2) = (4π/3)(36 + 24 + 16) = 304π/3 cm3.

Open this question

Question 34

Mensuration of Solids

In the diagram above, a cylinder is surmounted by a hemispherical bowl. Calculate the volume of the solid.

Diagram for this question
  1. A.180πcm3
  2. B.162πcm3
  3. C.216πcm3
  4. D.198πcm3
Show the answer and explanation

Answer: D (198πcm3)

Explanation

The radius is 3 cm and the cylinder is 20 cm high. Cylinder: π × 9 × 20 = 180π; hemisphere: (2/3)π × 27 = 18π. Total 198π cm3.

Open this question

Question 35

Angles and Polygons

The sum of the interior angles of a polygon is 20 right angles. How many sides does the polygon have?

  1. A.12
  2. B.20
  3. C.40
  4. D.10
Show the answer and explanation

Answer: A (12)

Explanation

20 right angles = 1800°. Setting (n − 2) × 180° = 1800° gives n − 2 = 10, so n = 12.

Open this question

Question 36

Coordinate Geometry

Find the coordinate of the midpoint of x and y intercepts of the line 2y = 4x − 8.

  1. A.(2,0)
  2. B.(1,−2)
  3. C.(−1,−2)
  4. D.(1,2)
Show the answer and explanation

Answer: B ((1,−2))

Explanation

The line meets the x-axis at (2, 0) and the y-axis at (0, −4). The midpoint is (1, −2).

Open this question

Question 37

Trigonometry

A hunter 1.6m tall, views a bird on top of a tree at an angle 45°. If the distance between the hunter and the tree is 10.4m, find the height of the tree.

  1. A.9.0m
  2. B.12.0m
  3. C.8.8m
  4. D.10.4m
Show the answer and explanation

Answer: B (12.0m)

Explanation

Above eye level the height is 10.4 × tan 45° = 10.4 m. Adding the hunter's eye height of 1.6 m gives 12.0 m.

Open this question

Question 38

Mensuration of Solids

A solid hemisphere has radius 7cm. Find the total surface area. [π = 22/7]

  1. A.400cm2
  2. B.462cm2
  3. C.66cm2
  4. D.308cm2
Show the answer and explanation

Answer: B (462cm2)

Explanation

The total surface is the curved part 2πr2 plus the flat circle πr2, i.e. 3πr2 = 3 × 22/7 × 49 = 462 cm2.

Open this question

Question 39

Coordinate Geometry

Find the value of α if the line 2y − αx + 4 = 0 is perpendicular to the line y + (1/4)x − 7 = 0

  1. A.−4
  2. B.4
  3. C.8
  4. D.−8
Show the answer and explanation

Answer: C (8)

Explanation

The gradients are α/2 and −1/4. For perpendicular lines (α/2)(−1/4) = −1, so α = 8.

Open this question

Question 40

Triangles and Quadrilaterals

The triangle PQR above is

Diagram for this question
  1. A.an obtuse-angled triangle
  2. B.a scalene triangle
  3. C.an isosceles triangle
  4. D.an equilateral triangle
Show the answer and explanation

Answer: C (an isosceles triangle)

Explanation

The exterior angle at R is 128°, so ∠PRQ = 52°. Then ∠P = 180° − 76° − 52° = 52°. Two equal angles make the triangle isosceles.

Open this question

Question 41

Loci

The locus of a point P which is equidistant from two given points S and T is

  1. A.the perpendicular bisector of ST
  2. B.the angle bisector of PS and ST
  3. C.a perpendicular to ST
  4. D.a line parallel to ST
Show the answer and explanation

Answer: A (the perpendicular bisector of ST)

Explanation

All points the same distance from S and T lie on the perpendicular bisector of the line segment ST.

Open this question

Question 42

Measures of Central Tendency

Find the mean of the data: 7, −3, 4, −2, 5, −9, 4, 8, −6, 12

  1. A.3
  2. B.4
  3. C.1
  4. D.2
Show the answer and explanation

Answer: D (2)

Explanation

The ten numbers add up to 20, so the mean is 20 ÷ 10 = 2.

Open this question

Question 43

Probability

The venn diagram above shows the number of students offering Music and History in a class of 80 students. If a student is picked at random from the class, what is the probability that he offers Music only?

Diagram for this question
  1. A.0.38
  2. B.0.13
  3. C.0.50
  4. D.0.25
Show the answer and explanation

Answer: D (0.25)

Explanation

(30 − x) + x + (40 − x) + 20 = 80 gives x = 10. Music only is 30 − 10 = 20 students, so the probability is 20/80 = 0.25.

Open this question

Question 44

Measures of Dispersion

The range of the data k+2, k−3, k+4, k−2, k, k−5, k+3, k−1 and k+6 is

  1. A.10
  2. B.11
  3. C.6
  4. D.8
Show the answer and explanation

Answer: B (11)

Explanation

The largest value is k + 6 and the smallest is k − 5. The range is (k + 6) − (k − 5) = 11.

Open this question

Question 45

Probability

The probability of a student passing any examination is 2/3. If the student takes three examinations, what is the probability that he will not pass any of them?

  1. A.2/3
  2. B.4/9
  3. C.8/27
  4. D.1/27
Show the answer and explanation

Answer: D (1/27)

Explanation

The chance of failing one examination is 1 − 2/3 = 1/3. Failing all three: (1/3)3 = 1/27.

Open this question

Question 46

Data Presentation

The acres for rice, pineapples, cassava, cocoa and palm oil in a certain district are given respectively as 2, 5, 3, 11 and 9. What is the angle of the sector for cassava in a pie chart?

  1. A.108°
  2. B.180°
  3. C.36°
  4. D.60°
Show the answer and explanation

Answer: C (36°)

Explanation

The total is 30 acres and cassava has 3. Its angle is 3/30 × 360° = 36°.

Open this question

Question 47

Permutation and Combination

How many three-digit numbers can be formed from 32564 without any digit being repeated?

  1. A.120
  2. B.10
  3. C.20
  4. D.60
Show the answer and explanation

Answer: D (60)

Explanation

There are 5 different digits. Arranging 3 of them in order: 5 × 4 × 3 = 60.

Open this question

Question 48

Measures of Central Tendency

The mean of a set of six numbers is 60. If the mean of the first five is 50, find the sixth number in the set

  1. A.105
  2. B.100
  3. C.95
  4. D.110
Show the answer and explanation

Answer: D (110)

Explanation

The six numbers total 6 × 60 = 360 and the first five total 5 × 50 = 250. The sixth is 360 − 250 = 110.

Open this question

Question 49

Measures of Dispersion

Calculate the mean deviation of the set of numbers 7, 3, 14, 9, 7 and 8

  1. A.2⅙
  2. B.2½
  3. C.1⅙
  4. D.2⅓
Show the answer and explanation

Answer: D (2⅓)

Explanation

The mean is 48 ÷ 6 = 8. The distances from 8 are 1, 5, 6, 1, 1, 0, which add to 14. Mean deviation = 14 ÷ 6 = 2⅓.

Open this question

Question 50

Measures of Central Tendency

No. of days: 1, 2, 3, 4, 5, 6
No. of students: 20, x, 50, 40, 2x, 60
The distribution above shows the number of days a group of 260 students were absent from school in a particular term. How many students were absent for at least four days in the term?

  1. A.210
  2. B.40
  3. C.120
  4. D.160
Show the answer and explanation

Answer: D (160)

Explanation

20 + x + 50 + 40 + 2x + 60 = 260 gives 3x = 90, so x = 30. At least four days: 40 + 60 + 60 = 160 students.

Open this question