JAMB Mathematics Past Questions 2019

10 questions from the JAMB 2019 Mathematics paper, with answers and explanations. Tap "Show answer" under each one when you are ready.

JAMB 2019Question 1 · Algebraic Processes

Make q the subject of the formula in the equation

\frac{mn}{a ^{2}}

\frac{pq}{b ^{2}}

= 1

A.q = $\frac{b ^{2} ( mn - a ^{2} )}{a ^{2} p}$
B.q = $\frac{m ^{2} n - a ^{2}}{p ^{2}}$
C.q = $\frac{mn - 2 b ^{2}}{a ^{2}}$
D.q = $\frac{b ^{2} ( n ^{2} - m a ^{2} )}{n}$

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Answer: A. q = $\frac{b ^{2} ( mn - a ^{2} )}{a ^{2} p}$

Rearranging gives q = b²(mn-a²)/(a²p).

JAMB 2019Question 2 · Algebraic Processes

If f(x) =

3 x^{3}

4 x^{2}

+ x - 8, what is the value of f(-2)?

A.-24
B.30
C.-18
D.-50

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Answer: C. -18

f(-2)=-24+16-2-8=-18.

JAMB 2019Question 3 · Calculus

\frac{d}{d x} [lo g (4 x^{3} - 2 x)]

is equal to

A. $\frac{12 x - 2}{4 x ^{2}}$
B. $\frac{43 x ^{2} - 2 x}{7 x}$
C. $\frac{4 x ^{2} - 2}{7 x + 6}$
D. $\frac{12 x ^{2} - 2}{4 x ^{3} - 2 x}$

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Answer: D. $\frac{12 x ^{2} - 2}{4 x ^{3} - 2 x}$

d/dx[log(4x³-2x)] = (12x²-2)/(4x³-2x).

JAMB 2019Question 4 · Commercial Arithmetic

Tade bought 200 mangoes at 4 for ₦2.50. 30 out of the mangoes got spoilt and the remaining were sold at 2 for ₦2.40. Find the percentage profit or loss.

A.43.6% loss
B.35% profit
C.63.2% profit
D.28% loss

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Answer: C. 63.2% profit

Cost=125, revenue=204; %profit= $\frac{79}{125}$ ×100≈63.2%.

JAMB 2019Question 5 · Coordinate Geometry and Trigonometry

4 sin^{2} x - 3 = 0

, find the value of

x

, when

0^{\circ} \leq x \leq 9 0^{\circ}

A. $9 0^{\circ}$
B. $4 5^{\circ}$
C. $6 0^{\circ}$
D. $3 0^{\circ}$

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Answer: C. $6 0^{\circ}$

sin²x= $\frac{3}{4}$ gives sinx= $3$ /2, so x= $6 0^{\circ}$ .

JAMB 2019Question 6 · Geometry and Mensuration

The angles of a polygon are given by 2x, 5x, x and 4x respectively. The value of x is

A. $3 1^{\circ}$
B. $3 0^{\circ}$
C. $2 6^{\circ}$
D. $4 8^{\circ}$

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Answer: B. $3 0^{\circ}$

Sum of angles=360: 12x=360, x=30.

JAMB 2019Question 7 · Inequalities, Permutation, and Combination

Solve for x in

\frac{4 x - 6}{3}

≤

\frac{3 + 2 x}{2}

A.x ≤ 1 $\frac{1}{2}$
B.x ≤ $\frac{21}{2}$
C.x ≥ $\frac{21}{2}$
D.x ≥ 1 $\frac{1}{2}$

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Answer: B. x ≤ $\frac{21}{2}$

Clearing denominators gives 2x≤21, so x≤21/2.

JAMB 2019Question 8 · Number, Fractions, and Approximation

Simplify

8 1^{- \frac{3}{4}} \times 2 5^{\frac{1}{2}} \times 24 3^{\frac{2}{5}}

A. $\frac{2}{5}$
B. $\frac{3}{5}$
C. $\frac{5}{2}$
D. $\frac{5}{3}$

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Answer: D. $\frac{5}{3}$

$8 1^{- 3/4} = \frac{1}{27}$ , $2 5^{1/2} = 5$ , and $24 3^{2/5} = 9$ . Their product is $\frac{5}{3}$ .

JAMB 2019Question 9 · Number, Fractions, and Approximation

2^{x + y}

= 16 and

4^{x - y}

\frac{1}{32}

, find the values of x and y.

A.x = $\frac{3}{4}$ , y = $\frac{11}{4}$
B.x = $\frac{3}{4}$ , y = $\frac{13}{4}$
C.x = $\frac{2}{3}$ , y = $\frac{4}{5}$
D.x = $\frac{2}{3}$ , y = $\frac{13}{4}$

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Answer: B. x = $\frac{3}{4}$ , y = $\frac{13}{4}$

x+y=4 and x-y= $\frac{- 5}{2}$ give x= $\frac{3}{4}$ , y=13/4.

JAMB 2019Question 10 · Sequences, Series, and Variation

The nth term of a sequence is given by

2^{2 n - 1}

. Find the sum of the first four terms.

A.74
B.32
C.42
D.170

Show answer

Answer: D. 170

Terms: 2,8,32,128; sum=170.

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JAMB Mathematics Past Questions 2019

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