Mathematics questions and answers

Mathematics Questions and Answers

How good are you with figures and formulas? Find out with these Mathematics past questions and answers. This Test is useful for both job aptitude test candidates and students preparing for JAMB, WAEC, NECO or Post UTME.

526.

A circular arc subtends angle 150° at the centre of a circle of radius 12cm. Calculate the area of the sector of the arc.

A.

30\(\pi\) cm\(^2\)

B.

60\(\pi\) cm\(^2\)

C.

120\(\pi\) cm\(^2\)

D.

150\(\pi\) cm\(^2\)

Correct answer is B

Area of sector = \(\frac{\theta}{360°} \times \pi r^{2}\)

= \(\frac{150}{360} \times \pi \times 12^{2}\)

= 60\(\pi\) cm\(^{2}\)

527.

If \(N = \begin{pmatrix} 3 & 5 & -4 \\ 6 & -3 & -5 \\ -2 & 2 & 1 \end{pmatrix}\), find \(|N|\).

A.

65

B.

23

C.

17

D.

91

Correct answer is C

\(\begin{vmatrix} 3 & 5 & -4 \\ 6 & -3 & -5 \\ -2 & 2 & 1 \end{vmatrix}\)

= \(3(-3 - (-10)) - 5(6 - 10) + (-4)(12 - 6)\)

= \(21 + 20 - 24\)

= 17

528.

If X, Y can take values from the set (1, 2, 3 ,4), find the probability that the product of X and Y is not greater than 6

A.

\(\frac{5}{8}\)

B.

\(\frac{5}{16}\)

C.

\(\frac{1}{2}\)

D.

\(\frac{3}{8}\)

Correct answer is A

x 1 2 3 4
1 1* 2* 3* 4*
2 2* 4* 6* 8
3 3* 6* 9 12
4 4* 8 12 16

The numbers that are not greater than 6 are either less than 6 or equal to 6.

P(picking a number not greater than 6) = \(\frac{10}{16}\)

= \(\frac{5}{8}\)

529.

In the figure, PQRS is a rectangle. If the shaded area is 72 sq. cm, find h.

A.

12cm

B.

10cm

C.

8cm

D.

5cm

Correct answer is D

From the diagram, PQRS is a rectangle

Area of shaded part = 72sq.cm

But 72 = 3h - 4 + 6h - 4 + 4h

= 72 - 16h - 8

= 16h - 72 + 8

=16h = 80

h = \(\frac{80}{16}\)

= 5cm

530.

Solve \(5^{2(x - 1)} \times 5^{x + 1} = 0.04\)

A.

\(\frac{1}{3}\)

B.

\(\frac{1}{4}\)

C.

\(-\frac{1}{5}\)

D.

\(-\frac{1}{3}\)

Correct answer is D

\(5^{2(x - 1)} \times 5^{x + 1} = 0.04\)

\(5^{2x - 2} \times 5^{x + 1} = 5^{-2}\)

\(2x - 2 + x + 1 = -2\)

\(3x - 1 = -2 \implies 3x = -2 + 1 = -1\)

\(x = -\frac{1}{3}\)