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.

3,636.

Simplify \(\frac{5+\sqrt{7}}{3+\sqrt{7}}\)

A.

17-√7

B.

4-√7

C.

15+√7

D.

7-√7

Correct answer is B

\(\frac{5+\sqrt{7}}{3+\sqrt{7}}=\frac{5+\sqrt{7}}{3+\sqrt{7}}\times \frac{3-\sqrt{7}}{3-\sqrt{7}}\\
=\frac{(5+\sqrt{7})(3-\sqrt{7})}{3^2 - \sqrt{7}^2}\\
=\frac{15-5\sqrt{7}+3\sqrt{7}-7}{9-7}\\
=\frac{8-2\sqrt{7}}{2}\)
Factorize then divide by 2
\(=\frac{2(4-\sqrt{7}}{2}\\
=4-\sqrt{7}\)

3,637.

If log\(_{10}\)2 = 0.3010 and log\(_{10}\)7 = 0.8451, evaluate log\(_{10}\)280

A.

3.4471

B.

2.4471

C.

1.4471

D.

1.4071

Correct answer is B

Log 2 = 0.3010, Log 7 = 0.8451
∴Log 280 = Log 28 x 10
= Log 7x4x10
=Log7 + Log4 + Log10
= Log7 + Log2\(^2\) + Log10
= Log7 + 2Log2 + Log10
= 0.8451 + 2(0.3010) + 1
= 0.8451 + 0.6020 + 1
= 2.4471

3,638.

A student spent 1/5 of his allowance on books, 1/2 of remainder on food and kept the rest for contingencies. What fraction was kept?

A.

7/15

B.

8/15

C.

2/5

D.

4/5

Correct answer is C

Let his allowance = y.

\(Books = \frac{y}{5}\)

\(Remainder: y - \frac{y}{5} = \frac{4y}{5}\)

\(Food: \frac{1}{2} \times \frac{4y}{5} = \frac{2y}{5}\)

\(Contingencies: \frac{4y}{5} - \frac{2y}{5} = \frac{2y}{5}\)

Therefore, he kept \(\frac{2}{5}\) of his allowance for contingencies.

3,639.

A man bought a second-hand photocopying machine for N34,000. He serviced it at a cost of N2,000 and then sold it at a profit of 15%. What was the selling price?

A.

N37,550

B.

N40,400

C.

N41,400

D.

N42,400

Correct answer is C

C.P = N34000 + N2000 = N36000
Gain = 100 + 15 = 115%
S.P = \(\frac{115}{100}\times \frac{N3600}{1}\)
= N41400

3,640.

Evaluate \(\frac{81.81+99.44}{20.09+36.16}\) correct to 3 significant figures.

A.

6.24

B.

3.22

C.

2.78

D.

2.13

Correct answer is B

\(\frac{81.81 + 99.44}{20.09 + 36.16}\\
=\frac{181.25}{56.25}\\
=\frac{18125}{5625}\\
\frac{29}{9}\\
=3\frac{2}{9}\\
≅ 3.22\)