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.

2,176.

Evaluate \(\frac{8^{\frac{1}{3}} \times 5^{\frac{2}{3}}}{10^{\frac{2}{3}}}\) 

A.

\(\frac{2}{5}\)

B.

\(\frac{5}{3}\)

C.

3\(\sqrt{5}\)

D.

3\(\sqrt{2}\)

Correct answer is D

\(\frac{8^{\frac{1}{3}} \times 5^{\frac{3}{2}}}{\frac{2}{10^3}}\) = \(\frac{(2^3)^{\frac{1}{3}} \times 5^{\frac{3}{2}}}{(2 \times 5)^{\frac{2}{3}}}\)

= \(\frac{2 \times 5}{2^{\frac{2}{3}} \times 5^{\frac{3}{2}}}\)

= 21 - \(\frac{2}{3}\)

= 2\(\frac{1}{3}\)

= 3\(\sqrt{2}\)

2,177.

A tax payer is allowed \(\frac{1}{8}\)th of his income tax-free, and pays 20% on the remainder. If he pays N490.00 tax, what is his income?

A.

N560.00

B.

N2,450.00

C.

N2,800.00

D.

N3,920.00

Correct answer is C

He pays tax on 1 - \(\frac{1}{8}\) = \(\frac{7}{8}\)th of his income

20% is 490, 100% is \(\frac{100}{20}\) x 490, N2,450.00

= \(\frac{7}{8}\) of his income = N2,450.00


\(\frac{1}{\frac{7}{8}}\) x 2450

= \(\frac{8 \times 2450}{7}\)

= \(\frac{19600}{7}\)

= N2800.00

2,178.

A basket contain green, black and blue balls in the ratio 5 : 2 : 1. If there are 10 blue balls. Find the corresponding new ratio when 10 green and 10 black balls are removed from the basket

A.

1 : 1 : 1

B.

4 : 2 : 1

C.

5 : 1 : 1

D.

4 : 1 : 1

Correct answer is D

Let x represent total number of balls in the basket.

If there are 10 blue balls, \(\frac{1}{8}\) of x = 10

x = 10 x 8 = 80 balls

Green balls will be \(\frac{5}{8}\) x 80 = 50 and black balls = \(\frac{2}{8}\) x 80 = 20

Ratio = Green : black : blue

50 : 20 : 10

-10 : -10 : -
------------------
New Ratio 40 : 10 : 10

4 : 1 : 1

2,179.

Two sisters, Taiwo and Keyinde, own a store. The ratio of Taiwo's share to Kehinde's is 11:9. Later, Keyinde sells \(\frac{2}{3}\) of her share to Taiwo for N720.00. Find the value of the store.

A.

N1,080.00

B.

N2,400.00

C.

N3,000.00

D.

N3,600.00

Correct answer is B

Let value of store = X

Ratio of Taiwo's share to kehine's is 11:9 Keyinde sells \(\frac{2}{3}\) of her share to Taiwo for N720

\(\frac{2}{3}\) of 9 = 6

∴ Sum of the ratio = 11 + 9 = 20

\{\frac{6}{20}\) of x = N720

\(\frac{6x}{20}\) = 720

∴ x = \(\frac{720 \times 20}{6}\)

x = N24,000

2,180.

A 5.0g of salt was weighted by Tunde as 5.1g. What is the percentage error?

A.

20

B.

2

C.

1.1

D.

0.2

Correct answer is B

% error = \(\frac{\text{actual error}}{\text{true value}}\) x 100

Where actual error = 5.1 - 5.0 = 0.1

true value = 5.0g

% error = \(\frac{0.1}{5.0}\) x 100

= \(\frac{10}{5}\)

= 2%