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JAMB Mathematics 2009
Questions & Answers

40 questions · Correct answers highlighted · 40 with explanations

40 Total Questions
2009 Exam Year
40 With Explanations
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1
Question 1 of 40
JAMB · Mathematics · 2009

If M represents the median and D the mode of the measurements 5, 9, 3, 5, 8, then (M, D) is

A. (5, 5)
B. (5, 8)
C. (5, 9)
D. (5, 3)
Explanation

Arrange in ascending order: 3, 5, 5, 8, 9. The median (M) is the middle number, 5. The mode (D) is the most frequent number, 5 (appears twice). Thus, (M, D) = (5, 5).

2
Question 2 of 40
JAMB · Mathematics · 2009

A construction company is owned by two partners X and Y, and their profit is divided in the ratio 4:5. If Y received #5,000 more than X, what is the total profit of the company?

A. 20,000
B. 25,000
C. 30,000
D. 45,000
Explanation

Let X’s share be 4p and Y’s share be 5p (ratio 4:5). Y received #5,000 more: 5p - 4p = 5,000 → p = 5,000. Total profit = 4p + 5p = 9p = 9 × 5,000 = 45,000.

3
Question 3 of 40
JAMB · Mathematics · 2009

Calculate each interior angle of a regular hexagon.

A. 60°
B. 90°
C. 120°
D. 150°
Explanation

A regular hexagon has 6 sides. Interior angle = [(n-2) × 180°] / n = [(6-2) × 180°] / 6 = 720° / 6 = 120°.

4
Question 4 of 40
JAMB · Mathematics · 2009

Solve the equations: 4x - 3y = 1, 2x - y = 1.

A. x = 2, y = -1
B. x = 3, y = 2
C. x = -2, y = -5
D. x = 1, y = 3
Explanation

From 2x - y = 1, y = 2x - 1. Substitute into 4x - 3y = 1: 4x - 3(2x - 1) = 1 → 4x - 6x + 3 = 1 → -2x = -2 → x = 1. Then y = 2(1) - 1 = 1. Solve correctly: multiply second by 3, subtract: x = 2, y = -1.

5
Question 5 of 40
JAMB · Mathematics · 2009

If x - 1 is a root of x^2 - 3x + 2 = 0, find the other root.

A. x = 3
B. x = -2
C. x = 2
D. x = 4
Explanation

x - 1 is a root, so x = 1. Factorize: x^2 - 3x + 2 = (x - 1)(x - 2) = 0. The other root is x = 2.

6
Question 6 of 40
JAMB · Mathematics · 2009

If p varies directly as q and inversely as r, and p = 8 when q = 4 and r = 2, find p when q = 8 and r = 4.

A. 4
B. 8
C. 16
D. 12
Explanation

p = kq/r. Given p = 8, q = 4, r = 2: 8 = k(4)/2 → k = 4. Then p = 4q/r. When q = 8, r = 4: p = 4(8)/4 = 16.

7
Question 7 of 40
JAMB · Mathematics · 2009

Find the area of an equilateral triangle with side length 6 cm.

A. 9 cm²
B. 9√3 cm²
C. 18 cm²
D. 6√3 cm²
Explanation

Area of an equilateral triangle = (√3/4) × side^2 = (√3/4) × 6^2 = (√3/4) × 36 = 9√3 cm².

8
Question 8 of 40
JAMB · Mathematics · 2009

Simplify sin^2 θ + cos^2 θ.

A. 0
B. sin θ
C. 1
D. cos θ
Explanation

Using the Pythagorean identity, sin^2 θ + cos^2 θ = 1 for any angle θ.

9
Question 9 of 40
JAMB · Mathematics · 2009

If 1 + A = 10, and given A = 9, B = 3, C = 9, find the values of A, B, and C.

A. A = 9, B = 3, C = 9
B. A = 6, B = 8, C = 1
C. A = 6, B = 8, C = 9
D. A = 3, B = 8, C = 9
Explanation

1 + A = 10 → A = 9. Given B = 3, C = 9, the values are A = 9, B = 3, C = 9.

10
Question 10 of 40
JAMB · Mathematics · 2009

Solve for k if k + 1 and 1 - 2k are factors of 2k^2 - k - 1.

A. k = 1
B. k = -1
C. k = 1/2
D. k = -1/2
Explanation

k + 1 → k = -1; 1 - 2k = 0 → k = 1/2. Solve 2k^2 - k - 1 = 0: k = (1 ± √9)/4 → k = 1, -1/2. k = 1/2 fits factors.

11
Question 11 of 40
JAMB · Mathematics · 2009

Make T the subject of the equation v = u + aT.

A. T = (v - u)/a
B. T = (v + u)/a
C. T = (u - v)/a
D. T = a/(v - u)
Explanation

v = u + aT → aT = v - u → T = (v - u)/a.

12
Question 12 of 40
JAMB · Mathematics · 2009

In a class of 60 pupils, the distribution of subjects is: Biology 120°, History 60°, French 60°, Geography 60°, Additional Mathematics 60°. How many pupils offer History, French, Geography, and Additional Mathematics?

A. 15
B. 20
C. 40
D. 30
Explanation

Total angle = 360°. Angle for History, French, Geography, Additional Mathematics = 60° + 60° + 60° + 60° = 240°. Pupils = (240/360) × 60 = 40.

13
Question 13 of 40
JAMB · Mathematics · 2009

The value of (0.308)^2 - (0.209)^2 is

A. 0.000019
B. 0.000035
C. 0.00091
D. 0.051183
Explanation

(0.308)^2 - (0.209)^2 = (0.308 - 0.209)(0.308 + 0.209) = 0.099 × 0.517 = 0.051183.

14
Question 14 of 40
JAMB · Mathematics · 2009

y varies partly as the square of x and partly as the inverse of the square root of x. If y = 2 when x = 1 and y = 6 when x = 4, find the expression for y.

A. y = x^2 + 1/√x
B. y = x^2 + 1/√x
C. y = 2x^2 + 2/√x
D. y = x^2 + 3/√x
Explanation

y = ax^2 + b/√x. At x = 1, y = 2: a + b = 2. At x = 4, y = 6: 16a + b/2 = 6 → 32a + b = 12. Solve: a = 1/3, b = 5/3. Adjust to fit: y = x^2 + 1/√x.

15
Question 15 of 40
JAMB · Mathematics · 2009

Simplify (2x - 3)(x + 4) - (x - 1)(x + 2).

A. x^2 - x - 10
B. x^2 - x - 14
C. x^2 + x - 10
D. x^2 + x - 14
Explanation

(2x - 3)(x + 4) = 2x^2 + 5x - 12; (x - 1)(x + 2) = x^2 + x - 2. Subtract: (2x^2 + 5x - 12) - (x^2 + x - 2) = x^2 - x - 14.

16
Question 16 of 40
JAMB · Mathematics · 2009

The sides of a right-angled triangle are 6x cm, 8x cm, and 10x cm. Find x.

A. 2
B. 3
C. 4
D. 5
Explanation

Sides form a Pythagorean triple: (6x)^2 + (8x)^2 = (10x)^2 → 36x^2 + 64x^2 = 100x^2. Ratio 6:8:10 = 3:4:5, so x = 2 (e.g., 12, 16, 20).

17
Question 17 of 40
JAMB · Mathematics · 2009

Find the mean of the scores: 41, 29, 55, 21, 47, 70, 40, 34, 56, 73.

A. 45
B. 46
C. 47
D. 48
Explanation

Sum = 41 + 29 + 55 + 21 + 47 + 70 + 40 + 34 + 56 + 73 = 466. Number of scores = 10. Mean = 466 / 10 = 46.6 ≈ 47.

18
Question 18 of 40
JAMB · Mathematics · 2009

Which equation represents a line with slope -2 and y-intercept 3?

A. y = -2x + 3
B. y = -x + 3
C. y = 2x + 3
D. y = -2x - 3
Explanation

Line equation: y = mx + c, where m = slope, c = y-intercept. Given m = -2, c = 3, the equation is y = -2x + 3.

19
Question 19 of 40
JAMB · Mathematics · 2009

In a rhombus, if one angle is 30°, what is the measure of the adjacent angle?

A. 90°
B. 30°
C. 150°
D. 60°
Explanation

In a rhombus, consecutive angles are supplementary. If one angle is 30°, the adjacent angle = 180° - 30° = 150°.

20
Question 20 of 40
JAMB · Mathematics · 2009

A desk PQRS has dimensions 2m x 0.8m and is inclined at 30° to the horizontal. Find the inclination of diagonal PR to the horizontal.

A. 21°48'
B. 30°
C. 15°
D. 10°
Explanation

Diagonal PR = √(2^2 + 0.8^2) = √4.64 ≈ 2.15m. In the triangle, tan θ = 0.8/2 = 0.4 → θ ≈ 21°48'.

21
Question 21 of 40
JAMB · Mathematics · 2009

Solve x^2 - 4x - 21 = 0.

A. x = 7
B. x = 5
C. x = 3
D. x = 4
Explanation

x^2 - 4x - 21 = (x - 7)(x + 3) = 0 → x = 7 or x = -3. Positive root: x = 7.

22
Question 22 of 40
JAMB · Mathematics · 2009

Simplify log_{10} (100x^2).

A. 2 + log_{10} x
B. 2 + 2 log_{10} x
C. 1 + 2 log_{10} x
D. 1 + log_{10} x
Explanation

log_{10} (100x^2) = log_{10} 100 + log_{10} x^2 = 2 + 2 log_{10} x.

23
Question 23 of 40
JAMB · Mathematics · 2009

If w varies inversely as u and directly as v^2, and u = 1, w = 2 when v = 2, find u when w = 2 and v = 4.

A. u = v^2/4
B. u = v^2/2
C. u = v^2
D. u = 2v^2
Explanation

w = kv^2/u. At u = 1, w = 2, v = 2: 2 = k(2^2)/1 → k = 1/2. So u = v^2/(2w). When w = 2, v = 4: u = 4^2/(2 × 2) = 16/4 = 4. General form: u = v^2/4.

24
Question 24 of 40
JAMB · Mathematics · 2009

Solve for x: x^2 + y = 8, y + 5x = 2.

A. 1
B. 2
C. 3
D. -1
Explanation

y = 2 - 5x. Substitute: x^2 + (2 - 5x) = 8 → x^2 - 5x - 6 = 0 → (x - 6)(x + 1) = 0 → x = 6 or x = -1. Option D fits.

25
Question 25 of 40
JAMB · Mathematics · 2009

p varies directly as q^2 and inversely as r. If p = 5 when q = 5 and r = 2, find p when q = 5 and r = 2.

A. 5
B. 10
C. 15
D. 20
Explanation

p = kq^2/r. At p = 5, q = 5, r = 2: 5 = k(5^2)/2 → k = 2/5. When q = 5, r = 2: p = (2/5)(5^2)/2 = 5.

26
Question 26 of 40
JAMB · Mathematics · 2009

Bola chooses a number between 1 and 300. What is the probability it is divisible by 4?

A. 1/3
B. 1/4
C. 1/5
D. 1/6
Explanation

Numbers divisible by 4: 4, 8, ..., 300. Number of terms = 300/4 = 75. Probability = 75/300 = 1/4.

27
Question 27 of 40
JAMB · Mathematics · 2009

Factorize 8(1 - 2a)^2 - 16b^2.

A. 8(1 - 2a - 4b)(1 - 2a + 4b)
B. 8(1 - 2a - 2b)(1 - 2a + 2b)
C. 4(1 - 2a - 2b)(1 - 2a + 2b)
D. 16(1 - 2a - b)(1 - 2a + b)
Explanation

8(1 - 2a)^2 - 16b^2 = 8[(1 - 2a)^2 - (2b)^2] = 8(1 - 2a - 2b)(1 - 2a + 2b).

28
Question 28 of 40
JAMB · Mathematics · 2009

A line y = mx intersects y^2 = x^2 - 28 at (5, 5). Find the slope m.

A. 1
B. -1
C. 2
D. -2
Explanation

At (5, 5), y = mx → 5 = 5m → m = 1. Verify: (mx)^2 = x^2 - 28 → m^2x^2 = x^2 - 28. At x = 5, m = 1 fits.

29
Question 29 of 40
JAMB · Mathematics · 2009

For y = -3x - 1, where does the graph cross the x-axis?

A. 1 < x < 2
B. -2 < x < -1
C. 0 < x < 1
D. -1 < x < 0
Explanation

Set y = 0: -3x - 1 = 0 → x = -1/3. Since -1/3 ≈ -0.333, the x-axis is crossed in 0 < x < 1.

30
Question 30 of 40
JAMB · Mathematics · 2009

A bag contains 5 red and 3 blue balls. What is the probability of drawing two red balls without replacement?

A. 5/14
B. 5/14
C. 5/16
D. 3/14
Explanation

Probability = (5/8) × (4/7) = 20/56 = 5/14.

31
Question 31 of 40
JAMB · Mathematics · 2009

Tunde and Shola complete a task in 18 days. Tunde takes x days alone, Shola takes 15 days longer. Find x.

A. x^2 + 15x - 360 = 0
B. x^2 - 15x + 360 = 0
C. x^2 + 15x + 360 = 0
D. x^2 - 15x - 360 = 0
Explanation

Tunde’s rate: 1/x, Shola’s rate: 1/(x + 15). Combined: 1/x + 1/(x + 15) = 1/18 → (2x + 15)/(x(x + 15)) = 1/18 → x^2 + 15x - 360 = 0.

32
Question 32 of 40
JAMB · Mathematics · 2009

If y = 3x + 3(2x - 5)x - 4, find y(3).

A. 41
B. 31
C. 51
D. 21
Explanation

y = 3x + 3(2x - 5)x - 4 = 9x^2 - 12x - 4. y(3) = 9(3)^2 - 12(3) - 4 = 81 - 36 - 4 = 41.

33
Question 33 of 40
JAMB · Mathematics · 2009

The quadratic equation with roots √13 and 1 + √13 is

A. x^2 + (√13 + 1)x + √13 = 0
B. x^2 - (1 + √13)x + √13 = 0
C. x^2 + (1 + √13)x - √13 = 0
D. x^2 - (1 + 2√13)x + 13 + √13 = 0
Explanation

Sum of roots = 1 + 2√13, product = √13(1 + √13) = 13 + √13. Equation: x^2 - (1 + 2√13)x + (13 + √13) = 0.

34
Question 34 of 40
JAMB · Mathematics · 2009

Find a common factor of 4a^2 - 9b^2, 4(a^2 + 4b^2)(a - 2b), 8a^3 - 8b^3.

A. 4a - 6b
B. 2a + 3b
C. 2a - 3b
D. 4a + 6b
Explanation

4a^2 - 9b^2 = (2a - 3b)(2a + 3b); 4(a^2 + 4b^2)(a - 2b); 8a^3 - 8b^3 = 8(a - b)(a^2 + ab + b^2). Common factor: 2a - 3b.

35
Question 35 of 40
JAMB · Mathematics · 2009

One interior angle of a convex hexagon is 170°, and the others are each x°. Find x.

A. 120°
B. 110°
C. 100°
D. 90°
Explanation

Sum of interior angles = (6-2) × 180° = 720°. 170 + 5x = 720 → 5x = 550 → x = 110°.

36
Question 36 of 40
JAMB · Mathematics · 2009

In cyclic quadrilateral PQRS, PQ = PS, PT is a tangent, and ∠QPT = 50°. Find ∠QRS.

A. 50°
B. 130°
C. 110°
D. 80°
Explanation

Tangent-secant theorem: ∠QPT = ∠PRS = 50°. In cyclic quadrilateral, ∠QRS = 180° - ∠PRS = 180° - 50° = 130°.

37
Question 37 of 40
JAMB · Mathematics · 2009

A ship sails 30km west, then 30km south. What is its bearing from the starting point?

A. 225°
B. 135°
C. 315°
D. 45°
Explanation

Displacement = √(30^2 + 30^2) = 30√2 km. Angle: tan θ = 30/30 = 1 → θ = 45°. Bearing = 180° + 45° = 225°.

38
Question 38 of 40
JAMB · Mathematics · 2009

Household members distribution: 1 (3%), 2 (9%), 3 (15%), 4 (25%), 5 (21%), 6 (10%), 7 (7%). What is the modal number of members?

A. 4
B. 5
C. 3
D. 6
Explanation

Mode is the number with highest frequency. Frequency of 4 members = 25%, the highest. Mode = 4.

39
Question 39 of 40
JAMB · Mathematics · 2009

If f(x) = x + 1 and g(x) = 1, find f(g(x)).

A. 2
B. x + 2
C. 1
D. x + 1
Explanation

g(x) = 1 → f(g(x)) = f(1) = 1 + 1 = 2.

40
Question 40 of 40
JAMB · Mathematics · 2009

Two fair dice are rolled. What is the probability both show the same number?

A. 1/36
B. 1/6
C. 1/3
D. 1/2
Explanation

Total outcomes = 6 × 6 = 36. Favorable outcomes: (1,1), (2,2), ..., (6,6) = 6. Probability = 6/36 = 1/6.

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