JAMB Mathematics Past Questions & Answers

916.

Simplify 3 - 2 $\div$ $\frac{4}{5}$ + $\frac{1}{2}$

1 $\frac{3}{4}$

-1

1 $\frac{3}{10}$

1 $\frac{9}{10}$

Correct answer is D

3 - 2 $\div$ ( $\frac{4}{5}$ ) + $\frac{1}{2}$

3 - (2 x $\frac{5}{4}$ ) + $\frac{1}{2}$ = 3 - $\frac{10}{4}$ + $\frac{1}{2}$

= 3 - $\frac{5}{2}$ + $\frac{1}{2}$

= $\frac{6 - 5 + 1}{2}$

= $\frac{2}{2}$

= 1

917.

Rationalize the expression $\frac{1}{\sqrt{2} + \sqrt{5}}$

$\frac{1}{3}$ ( $\sqrt{5} - \sqrt{2}$

$\frac{\sqrt{2}}{3}$ + $\frac{\sqrt{5}}{5}$

$\sqrt{2} - \sqrt{5}$

5( $\sqrt{2} - \sqrt{5}$

$\frac{1}{3}$ ( $\sqrt{2} - \sqrt{5}$

View answer & explanation

Correct answer is A

$\frac{1}{\sqrt{2} + \sqrt{5}}$

$\frac{1}{\sqrt{2} + \sqrt{5}} \times \frac{(\sqrt{2} - \sqrt{5})}{(\sqrt{2} - \sqrt{5})}$

= $\frac{\sqrt{2} - \sqrt{5}}{2 - 5}$

= $\frac{\sqrt{2} - \sqrt{5}}{-3}$

= $\frac{1}{3} (\sqrt{5} - \sqrt{2})$

918.

A man drove for 4 hours at a certain speed, he then doubled his speed and drove for another 3 hours. Although he covered 600 kilometers. At what speed did he drive for the last 3 hours?

120km/hr

60km/hr

670km/hr

40km/hr

View answer & explanation

Correct answer is B

Speed = $\frac{distance}{time}$

let x represent the speed, d represent distance

x = $\frac{d}{4}$

d = 4x

2x = $\frac{600 - d}{3}$

6x = 600 - d

6x = 600 - 4x

10x = 600

x = $\frac{600}{10}$

= 60km/hr

919.

Find the mean of the following 24.57, 25.63, 24.32, 26.01, 25.77

25.12

25.30

25.26

25.50

25.75

View answer & explanation

Correct answer is C

$\frac{24.57 + 25.63 + 24.32 + 26.01 + 25.77}{5}$

mean = $\frac{126.3}{5}$

= 25.26

920.

In a triangle PQT, QR = $\sqrt{3}cm$ , PR = 3cm, PQ = $2\sqrt{3}$ cm and PQR = 30°. Find angles P and R

P = 60^o and R = 90^o

P = 30^o and R = 120^o

P = 90^o and R = 60^o

P = 60^o and R 60^o

P = 45^o and R = 105^o

View answer & explanation

Correct answer is A

By using cosine formula, p2 = Q2 + R2 - 2QR cos p

Cos P = $\frac{Q^2 + R^2 - p^2}{2 QR}$

= $\frac{(3)^2 + 2(\sqrt{3})^2 - 3^2}{2\sqrt{3}}$

= $\frac{3 + 12 - 9}{12}$

= $\frac{6}{12}$

= $\frac{1}{2}$

= 0.5

Cos P = 0.5

p = cos-1 0.5 = 60°

= < P = 60°

If < P = 60° and < Q = 30

< R = 180° - 90°

angle P = 60° and angle R is 90°