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.

2,691.

A cylindrical tank has a capacity of 6160m3. What is the depth of the tank if the radius of its base is 28cm?

A.

8.0m

B.

7.5m

C.

5.0m

D.

2.5m

Correct answer is D

Using \(V = \pi r^2 h\)

6160 = 22/7 x 28 x 28 x h

\(h = \frac{6160}{22 \times 4 \times 28} \)

\(h = 2.5m \)

2,692.

How many sides has a regular polygon whose interior angle is 135°?

A.

12

B.

10

C.

9

D.

8

Correct answer is D

p>If each interior angle of the polygon is 135°, then each exterior angle is 180° - 135° = 45°.

Hence, number of sides =

\(\frac{360°}{\text{one exterior angle}}\)

\(\frac{360°}{45°}\)

= 8

2,693.

Find the value of \(\begin{vmatrix}0 & 3 & 2 \\1 & 7 & 8 \\0 & 5 & 4\end{vmatrix}\).

A.

12

B.

10

C.

-1

D.

-2

Correct answer is D

\(0 \begin{vmatrix}7 & 8 \\5 & 4\end{vmatrix} -3 \begin{vmatrix}1 & 8 \\0 & 4\end{vmatrix} +2 \begin{vmatrix}1 & 7 \\0 & 5\end{vmatrix}\)

= 0(28 - 40) - 3(4 - 0) + 2(5 - 0)

= 0(-12) - 3(4) + 2(5)

= 0 - 12 + 10

= -2

2,694.

If \(\begin{vmatrix}-x & 12 \\-1 & 4 \end{vmatrix} = - 12\), find x.

A.

-6

B.

-2

C.

3

D.

6

Correct answer is D

\(\begin{vmatrix}-x & 12 \\-1 & 4\end{vmatrix} = - 12\)

-4x - (-1)12 = -12

-4x + 12 = -12

-4x = -12 - 12

-4x = - 24

x = 6

2,695.

Find y, if \(\begin{pmatrix}5 & -6 \\2 & -7\end{pmatrix}\begin{pmatrix}x \\ y \end{pmatrix} = \begin{pmatrix}7 \\-11\end{pmatrix}\)

A.

8

B.

5

C.

3

D.

2

Correct answer is C

\(\begin{pmatrix}5 & -6 \\2 & -7\end{pmatrix}\begin{pmatrix} x \\ y \end{pmatrix} = \begin{pmatrix}7 \\-11\end{pmatrix}\)

By matrices multiplication;

5x - 6y = 7 ........(1)
2x - 7y = -11 ......(2)
2 x (1): 10x - 12y = 14 .......(3)
5 x (2): 10x - 35y = -55 ......(4)

(3) - (4): 23y = 69

y = 69/23 = 3