JAMB Mathematics 2010 past questions and answers

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

Question 2

Number Bases

Find r, if 6r78 = 5119.

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

Answer: C (3)

Explanation

6r78 = 384 + 8r + 7 and 5119 = 405 + 9 + 1 = 415. So 8r = 24 and r = 3.

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Question 3

Fractions, Decimals and Approximation

Simplify (3/4 of 4/9 ÷ 9½) ÷ 1 5/19.

  1. A.1/25
  2. B.1/4
  3. C.1/5
  4. D.1/36
Show the answer and explanation

Answer: D (1/36)

Explanation

3/4 of 4/9 = 1/3. 1/3 ÷ 19/2 = 2/57, and 2/57 ÷ 24/19 = 2/57 × 19/24 = 1/36.

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Question 4

Ratio, Percentages and Rates

A student measures a piece of rope and found that it was 1.26 m long. If the actual length of the rope was 1.25 m, what was the percentage error in the measurement?

  1. A.0.40%
  2. B.0.01%
  3. C.0.25%
  4. D.0.80%
Show the answer and explanation

Answer: D (0.80%)

Explanation

The error is 0.01 m, so the percentage error is 0.01/1.25 × 100% = 0.8%.

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Question 5

Commercial Arithmetic

At what rate will the interest on N400 increase to N24 in 3 years reckoning in simple interest?

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

Answer: B (2%)

Explanation

R = 100I/(PT) = 100 × 24/(400 × 3) = 2%.

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Question 6

Ratio, Percentages and Rates

If p:q = 2/3 : 5/6 and q : r = 3/4 : 1/2, find p:q:r.

  1. A.9:10:15
  2. B.12:15:16
  3. C.12:15:10
  4. D.10:15:24
Show the answer and explanation

Answer: C (12:15:10)

Explanation

p : q = 4 : 5 = 12 : 15 and q : r = 3 : 2 = 15 : 10. So p : q : r = 12 : 15 : 10.

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Question 7

Indices

Evaluate (81/16)−¼ × 2−1.

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

Answer: A (1/3)

Explanation

(81/16)¼ = 3/2, so (81/16)−¼ = 2/3. Then 2/3 × ½ = 1/3.

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Question 8

Logarithms

Given that log 2 = 0.3010, log 7 = 0.8451. Evaluate log 112.

  1. A.2.5441
  2. B.2.0491
  3. C.2.1461
  4. D.3.1461
Show the answer and explanation

Answer: B (2.0491)

Explanation

112 = 24 × 7, so log 112 = 4(0.3010) + 0.8451 = 2.0491.

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Question 9

Surds

Rationalize (2√3 + √5)/(√5 − √3)

  1. A.(3√15 + 11)/2
  2. B.(3√15 − 11)/2
  3. C.3√15 − 11
  4. D.3√15 + 11
Show the answer and explanation

Answer: A ((3√15 + 11)/2)

Explanation

Multiply top and bottom by √5 + √3: (2√15 + 6 + 5 + √15)/(5 − 3) = (3√15 + 11)/2.

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Question 10

Fractions, Decimals and Approximation

Express the product of 0.21 and 0.34 in standard form

  1. A.7.14 × 10−3
  2. B.7.14 × 10−1
  3. C.7.14 × 10−2
  4. D.7.14 × 10−4
Show the answer and explanation

Answer: C (7.14 × 10−2)

Explanation

0.21 × 0.34 = 0.0714 = 7.14 × 10−2.

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Question 11

Sets

Which of the Venn diagrams below represents P'∩Q∩R'?

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

Answer: A (Diagram A)

Explanation

P' ∩ Q ∩ R' is the part of Q that is outside both P and R, which is the region shaded in A.

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Question 12

Sets

In a survey of 50 newspaper readers, 40 read Champion and 30 read Guardian, how many read both papers?

  1. A.15
  2. B.5
  3. C.10
  4. D.20
Show the answer and explanation

Answer: D (20)

Explanation

Both = 40 + 30 − 50 = 20.

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Question 13

Algebraic Expressions

Make Q the subject of the formula if P = (M/5)(X + Q) + 1.

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

Answer: B ((5P − MX − 5)/M)

Explanation

5P = MX + MQ + 5, so MQ = 5P − MX − 5 and Q = (5P − MX − 5)/M.

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Question 14

Polynomials

If 9x2 + 6xy + 4y2 is a factor of 27x3 − 8y3, find the other factor.

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

Answer: A (3x − 2y)

Explanation

Difference of two cubes: 27x3 − 8y3 = (3x − 2y)(9x2 + 6xy + 4y2).

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Question 15

Algebraic Expressions

Factorize completely (x3 + 3x2 − 10x)/(2x2 − 8)

  1. A.(x2 + 5)/(2x + 4)
  2. B.x(x + 5)/2(x + 2)
  3. C.x(x − 5)/2(x + 2)
  4. D.x(x − 5)/2(x − 2)
Show the answer and explanation

Answer: B (x(x + 5)/2(x + 2))

Explanation

The top is x(x2 + 3x − 10) = x(x + 5)(x − 2) and the bottom is 2(x − 2)(x + 2). Cancelling (x − 2) leaves x(x + 5)/2(x + 2).

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Question 16

Linear and Simultaneous Equations

Solve for x and y if x − y = 2 and x2 − y2 = 8

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

Answer: B ((3, 1))

Explanation

x2 − y2 = (x − y)(x + y), so 2(x + y) = 8 and x + y = 4. With x − y = 2 this gives x = 3, y = 1.

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Question 17

Variation

If y varies directly as the square root of x and y = 3 when x = 16. Calculate y when x = 64.

  1. A.5
  2. B.12
  3. C.6
  4. D.3
Show the answer and explanation

Answer: C (6)

Explanation

y = k√x: 3 = 4k, so k = ¾. When x = 64, y = ¾ × 8 = 6.

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Question 18

Variation

If x is inversely proportional to y and x = 2½ when y = 2, find x if y = 4.

  1. A.2¼
  2. B.5
  3. C.4
  4. D.1¼
Show the answer and explanation

Answer: D (1¼)

Explanation

xy is constant: 2½ × 2 = 5. So x = 5/4 = 1¼.

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Question 19

Inequalities

For what range of values of x is ½x + ¼ > ⅓x + ½?

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

Answer: B (x > 3/2)

Explanation

½x − ⅓x > ½ − ¼ gives x/6 > ¼, so x > 3/2.

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Question 20

Inequalities

Solve the inequalities −6 ≤ 4 − 2x < 5 − x.

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

Answer: B (−1 < x ≤ 5)

Explanation

−6 ≤ 4 − 2x gives x ≤ 5. 4 − 2x < 5 − x gives x > −1. So −1 < x ≤ 5.

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Question 21

Progressions

Find the sum to infinity of the following series. 0.5 + 0.05 + 0.005 + 0.0005...

  1. A.5/9
  2. B.5/7
  3. C.5/8
  4. D.5/11
Show the answer and explanation

Answer: A (5/9)

Explanation

a = 0.5 and r = 0.1, so S = 0.5/0.9 = 5/9.

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Question 22

Progressions

The 3rd term of an arithmetic progression is −9 and the 7th term is −29. Find the 10th term of the progression.

  1. A.44
  2. B.−165
  3. C.−44
  4. D.165
Show the answer and explanation

Answer: C (−44)

Explanation

a + 2d = −9 and a + 6d = −29 give d = −5 and a = 1. The 10th term = 1 + 9(−5) = −44.

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Question 23

Binary Operations

If x * y = x + y2, find the value of (2*3)*5.

  1. A.36
  2. B.11
  3. C.25
  4. D.55
Show the answer and explanation

Answer: A (36)

Explanation

2 * 3 = 2 + 9 = 11, then 11 * 5 = 11 + 25 = 36.

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Question 24

Algebraic Expressions

If p and q are two non- zero numbers and 18(p+q) = (18+p)q, which of the following must be true?

  1. A.q = 18
  2. B.p = 18
  3. C.p<1
  4. D.q<1
Show the answer and explanation

Answer: A (q = 18)

Explanation

18p + 18q = 18q + pq gives 18p = pq. Since p ≠ 0, q = 18.

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Question 25

Matrices and Determinants

If |x 3; 2 7| = 15, find the value of x. (Determinant written row by row.)

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

Answer: A (3)

Explanation

7x − 6 = 15, so 7x = 21 and x = 3.

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Question 26

Matrices and Determinants

Evaluate |2 0 5; 4 6 3; 8 9 1| (determinant written row by row)

  1. A.−42
  2. B.102
  3. C.18
  4. D.−102
Show the answer and explanation

Answer: D (−102)

Explanation

Expanding along the first row: 2(6 − 27) − 0 + 5(36 − 48) = −42 − 60 = −102.

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Question 27

Matrices and Determinants

If P = (2 −3; 1 1), what is P−1? (Matrices written row by row.)

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

Answer: B ((1/5 3/5; −1/5 2/5))

Explanation

The determinant is 2 + 3 = 5. Swap the diagonal and change the other signs: P−1 = 1/5 (1 3; −1 2) = (1/5 3/5; −1/5 2/5).

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Question 28

Triangles and Quadrilaterals

From the diagram above, find x.

Diagram for this question
  1. A.65°
  2. B.50°
  3. C.55°
  4. D.75°
Show the answer and explanation

Answer: A (65°)

Explanation

RS is a diameter, so ∠RTS = 90° and ∠RST = 180° − 90° − 25° = 65°. By the alternate segment theorem, the angle x between the tangent and chord TR equals ∠RST = 65°.

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Question 29

Angles and Polygons

The interior angles of a quadrilateral are (x + 15)°, (2x − 45)°, (x − 30)° and (x + 10)°. Find the value of the least interior angle.

  1. A.102°
  2. B.52°
  3. C.82°
  4. D.112°
Show the answer and explanation

Answer: B (52°)

Explanation

The angles add to 360°: 5x − 50 = 360, so x = 82. The angles are 97°, 119°, 52° and 92°; the least is 52°.

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Question 30

Circle Theorems

From the cyclic quadrilateral TUVW above, find the value of x.

Diagram for this question
  1. A.23°
  2. B.26°
  3. C.24°
  4. D.20°
Show the answer and explanation

Answer: C (24°)

Explanation

Opposite angles of a cyclic quadrilateral add to 180°: 3x + 20 + 88 = 180, so 3x = 72 and x = 24°.

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Question 31

Mensuration of Plane Shapes

If the two smaller sides of a right angled triangle are 4 cm and 5 cm, find its area.

  1. A.10 cm2
  2. B.6 cm2
  3. C.8 cm2
  4. D.24 cm2
Show the answer and explanation

Answer: A (10 cm2)

Explanation

The two shorter sides are the base and height, so area = ½ × 4 × 5 = 10 cm2.

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Question 32

Mensuration of Plane Shapes

An arc subtends an angle of 50° at the centre of circle of radius 6 cm. Calculate the area of the sector formed. (π = 22/7)

  1. A.90/7 cm2
  2. B.110/7 cm2
  3. C.100/7 cm2
  4. D.80/7 cm2
Show the answer and explanation

Answer: B (110/7 cm2)

Explanation

Area = 50/360 × 22/7 × 36 = 110/7 cm2.

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Question 33

Mensuration of Solids

A cylindrical pipe 50 m long with radius 7 m has one end open. What is the total surface area of the pipe?

  1. A.700π m2
  2. B.98π m2
  3. C.350π m2
  4. D.749π m2
Show the answer and explanation

Answer: D (749π m2)

Explanation

Curved surface = 2πrh = 2π × 7 × 50 = 700π. One closed end adds πr2 = 49π. Total = 749π m2.

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Question 34

Loci

What is the locus of points that is equidistant from points P(1, 3) and Q (3, 5)?

  1. A.y = −x + 6
  2. B.y = x + 6
  3. C.y = −x − 6
  4. D.y = x − 6
Show the answer and explanation

Answer: A (y = −x + 6)

Explanation

The locus is the perpendicular bisector of PQ. The midpoint is (2, 4) and PQ has gradient 1, so the bisector has gradient −1: y − 4 = −(x − 2), i.e. y = −x + 6.

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Question 35

Coordinate Geometry

Find the distance between the points (½, ½) and (−½, −½).

  1. A.√2
  2. B.0
  3. C.1
  4. D.√3
Show the answer and explanation

Answer: A (√2)

Explanation

d = √((½ + ½)2 + (½ + ½)2) = √(1 + 1) = √2.

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Question 37

Coordinate Geometry

Find the equation of a line parallel to y = −4x + 2 passing through (2,3).

  1. A.y − 4x + 11 = 0
  2. B.y − 4x − 11 = 0
  3. C.y + 4x + 11 = 0
  4. D.y + 4x − 11 = 0
Show the answer and explanation

Answer: D (y + 4x − 11 = 0)

Explanation

A parallel line has gradient −4: y − 3 = −4(x − 2), so y = −4x + 11, i.e. y + 4x − 11 = 0.

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Question 38

Trigonometry

If cot θ = 8/15, where θ is acute, find sin θ.

  1. A.13/15
  2. B.15/17
  3. C.8/17
  4. D.16/17
Show the answer and explanation

Answer: B (15/17)

Explanation

tan θ = 15/8, so the opposite side is 15, the adjacent 8 and the hypotenuse √(225 + 64) = 17. sin θ = 15/17.

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Question 39

Mensuration of Plane Shapes

If the area of ΔPQR above is 12√3 cm2, find the value of q?

Diagram for this question
  1. A.6 cm
  2. B.8 cm
  3. C.7 cm
  4. D.5 cm
Show the answer and explanation

Answer: A (6 cm)

Explanation

Area = ½ × 8 × q × sin 60° = 2√3 q. Setting 2√3 q = 12√3 gives q = 6 cm.

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Question 40

Differentiation

If y = (2x + 1)3, find dy/dx.

  1. A.3(2x + 1)2
  2. B.3(2x + 1)
  3. C.6(2x + 1)
  4. D.6(2x + 1)2
Show the answer and explanation

Answer: D (6(2x + 1)2)

Explanation

By the chain rule, dy/dx = 3(2x + 1)2 × 2 = 6(2x + 1)2.

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Question 42

Differentiation

At what value of x does the function y = −3 − 2x + x2 attain a minimum value?

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

Answer: A (1)

Explanation

dy/dx = −2 + 2x = 0 at x = 1, and the second derivative 2 is positive, so the minimum is at x = 1.

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Question 43

Integration

Evaluate ∫02 (x3 + x2) dx.

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

Answer: B (6 2/3)

Explanation

[x4/4 + x3/3] from 0 to 2 = 4 + 8/3 = 6 2/3.

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Question 44

Integration

Find ∫(sin x + 2)dx.

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

Answer: C (−cos x + 2x + k)

Explanation

∫sin x dx = −cos x and ∫2 dx = 2x, so the answer is −cos x + 2x + k.

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Question 45

Measures of Central Tendency

Marks: 2, 3, 4, 5, 6, 7, 8
No. of Students: 3, 1, 5, 2, 4, 2, 3
From the table above, if the pass mark is 5, how many students failed the test?

  1. A.7
  2. B.2
  3. C.6
  4. D.9
Show the answer and explanation

Answer: D (9)

Explanation

Students who scored below 5 failed: 3 + 1 + 5 = 9.

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Question 46

Measures of Central Tendency

Marks: 1, 2, 3, 4, 5
Frequencies: 2, 2, 8, 4, 4
The table above shows the marks obtained in a given test. How many students took the test?

  1. A.15
  2. B.20
  3. C.16
  4. D.13
Show the answer and explanation

Answer: B (20)

Explanation

Add the frequencies: 2 + 2 + 8 + 4 + 4 = 20.

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Question 47

Measures of Central Tendency

Marks: 1, 2, 3, 4, 5
Frequencies: 2, 2, 8, 4, 4
The table above shows the marks obtained in a given test. Find the mean mark.

  1. A.3.2
  2. B.3.0
  3. C.3.1
  4. D.3.3
Show the answer and explanation

Answer: D (3.3)

Explanation

Σfx = 2 + 4 + 24 + 16 + 20 = 66 and Σf = 20, so the mean is 66/20 = 3.3.

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Question 48

Measures of Dispersion

Find the standard deviation of 2, 3, 5 and 6.

  1. A.√(5/2)
  2. B.√10
  3. C.√6
  4. D.√(2/5)
Show the answer and explanation

Answer: A (√(5/2))

Explanation

The mean is 4. The squared deviations are 4, 1, 1, 4, total 10, so the variance is 10/4 = 5/2 and the SD is √(5/2).

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Question 49

Permutation and Combination

In how many ways can a committee of 2 women and 3 men be chosen from 6 men and 5 women?

  1. A.50
  2. B.200
  3. C.100
  4. D.30
Show the answer and explanation

Answer: B (200)

Explanation

5C2 × 6C3 = 10 × 20 = 200.

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Question 50

Probability

If three unbiased coins are tossed, find the probability that they are all heads.

  1. A.1/8
  2. B.1/3
  3. C.1/6
  4. D.1/9
Show the answer and explanation

Answer: A (1/8)

Explanation

Each coin is heads with probability ½, so all three is (½)3 = 1/8.

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