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.

521.

Find the length of a chord which subtends an angle of 90° at the centre of a circle whose radius is 8 cm.

A.

\(8\sqrt{3}\) cm

B.

4 cm

C.

8 cm

D.

\(8\sqrt{2}\) cm

Correct answer is D

Length of chord = \(2r \sin (\frac{\theta}{2})\)

= \(2 \times 8 \times \sin (\frac{90}{2})\)

= \(16 \times \frac{\sqrt{2}}{2}\)

= \(8\sqrt{2} cm\)

522.

A square tile has side 30 cm. How many of these tiles will cover a rectangular floor of length 7.2m and width 4.2m?

A.

720

B.

336

C.

420

D.

576

Correct answer is B

Length of the tile = 30 cm = 0.3m

Area of the tile = 0.3 \(\times\) 0,3 = 0.09 m\(^2\)

Area of the room = (7.2 \(\times\) 4.2)m\(^2\)

Number of tiles = \(\frac{7.2 \times 4.2}{0.09}\)

= 336

523.

If the angles of a quadrilateral are (3y + 10)°, (2y + 30)°, (y + 20)° and 4y°. Find the value of y.

A.

66°

B.

12°

C.

30°

D.

42°

Correct answer is C

Sum of angles in a quadrilateral = 360°

\(\therefore\) (3y + 10) + (2y + 30) + (y + 20) + 4y = 360

10y + 60 = 360 \(\implies\) 10y = 300

y = 30° 

524.

Find \(\frac{\mathrm d y}{\mathrm d x}\) if \(y = \cos x\).

A.

\(\sin x\)

B.

\(- \sin x\)

C.

\(\tan x\)

D.

\(- \tan x\)

Correct answer is B

If \(y = \cos x\)

\(\frac{\mathrm d y}{\mathrm d x}\) =—\(\sin x\)

525.

A man stands on a tree 150 cm high and sees a boat at an angle of depression of 74°. Find the distance of the boat from the base of the tree.

A.

52 cm

B.

43 cm

C.

40 cm

D.

15 cm

Correct answer is B

\(\tan 16 = \frac{x}{150}\)

\(x = 150 \tan 16\)

= \(43 cm\)