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.

2,231.

If a : b = 5 : 8, x : y = 25 : 16; evaluate \(\frac{a}{x}\) : \(\frac{b}{y}\)

A.

125 : 128

B.

3 : 5

C.

3 : 4

D.

2 : 5

Correct answer is D

a : b = 5 : 8 = 2.5 : 40

x : y = 25 : 16

\(\frac{a}{x}\) : \(\frac{b}{y}\) = \(\frac{25}{25}\) : \(\frac{40}{16}\)

= 1 : \(\frac{40}{16}\)

= 16 : 40

= 2 : 5

2,232.

What is the different between 0.007685 correct to three significant figures and 0.007685 correct to four places of decimal?

A.

10-5

B.

7 x 10-4

C.

8 x 10-5

D.

10-6

Correct answer is A

0.007685 = 0.00769 (three significant figures)

0.007685 = 0.0077(4d.p)

the difference = 0.0077 - 0.00769

= 0.00001

= 1.0 x 10-5

2,233.

Simplify \(\sqrt[3]{(64r^{-6})^{\frac{1}{2}}}\)

A.

\(\frac{r}{2}\)

B.

2r

C.

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

D.

\(\frac{2}{r}\)

Correct answer is B

\(\sqrt[3]{(64r^{-6})^{\frac{1}{2}}}\)

= \(((64r^{-6})^{1/_2})^{1/_3}\)

=\((64r^{-6})^{1/_6}\)

=\(64)^{1/_6}(r^{-6})^{1/_6}\)

=2/r

2,234.

If \(12_{e} = X_{7}\), where e = 12, find X.

A.

20

B.

15

C.

14

D.

12

Correct answer is A

\(12_{12} = 1 \times 12^{1} + 2 \times 12^{0} = 12 + 2 = 14_{10}\)

7 14
7 2 rm 0
  0 rm 2

\(\therefore 12_{e} = 20_{7}\)

 

2,235.

The prime factors of 2520 are

A.

2, 9, 5

B.

2, 9, 7

C.

2, 3, 5, 7

D.

2, 3, 7, 9

Correct answer is C

\(2520 = 2 \times 2 \times 2 \times 3 \times 3 \times 5 \times 7\) in terms of its prime factors. Hence, the prime factors of 2520 are 2, 3, 5, 7.