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.

641.

If \(\log_{10}\)(6x - 4) - \(\log_{10}\)2 = 1, solve for x.

A.

2

B.

3

C.

4

D.

5

Correct answer is C

\(\log_{10}\)(6x - 4) - \(\log_{10}\)2 = 1

\(\log_{10}\)(6x - 4) - \(\log_{10}\)2 = \(\log_{10}\)10

\(\log_{10}\)\(\frac{6x - 4}{2}\) - \(\log_{10}\)10

\(\frac{6x - 4}{2}\) = 10

6x - 4 = 2 x 10

= 20

6x = 20 + 4

6x = 20

x = \(\frac{24}{6}\)

x = 4

642.

There are 250 boys and 150 girls in a school, if 60% of the boys and 40% of the girls play football, what percentage of the school play football?

A.

40.0%

B.

42.2%

C.

50.0%

D.

52.5%

Correct answer is D

Population of school = 250 + 150 = 400

60% of 250 = \(\frac{\text{60%}}{\text{100%}}\) x 250 = 150

40% of 150 = \(\frac{\text{40%}}{\text{100%}}\) x 150 = 60

Total number of students who plays football;

150 + 60 = 210

Percentage of school that play football;

\(\frac{210}{400}\) x 100% = 52.5%

643.

Simplify; 2\(\frac{1}{4} \times 3\frac{1}{2} \div  4 \frac{3}{8}\)

A.

\(\frac{5}{9}\)

B.

1\(\frac{1}{5}\)

C.

1\(\frac{1}{4}\)

D.

1\(\frac{4}{5}\)

Correct answer is D

2\(\frac{1}{4} \times 3\frac{1}{2} \div  4 \frac{3}{8}\)

= \(\frac{9}{4} \times \frac{7}{2} \div \frac{35}{8}\)

= \(\frac{9}{4} \times \frac{7}{2} \div \frac{8}{35}\)

= \(\frac{9}{5}\)

= 1 \(\frac{4}{5}\)

644.

Find the value of x for which \(32_{four} = 22_x\)

A.

three

B.

five

C.

six

D.

seven

Correct answer is C

\(32_4 = 22_x\)

\(3 \times 4^1 + 2 \times 4^o\) = \(2 \times x^1 + 2 \times x^o\)

12 + 2 x 1 = 2x + 2 x 1

14 = 2x + 2

14 - 2 = 2x

12 = 2x

x = \(\frac{12}{2}\)

x = 6

645.

Given that y varies inversely as the square of x. If x = 3 when y = 100, find the equation connecting x and y.

A.

\(yx^2 = 300\)

B.

\(yx^2 = 900\)

C.

y = \(\frac{100x}{9}\)

D.

\(y = 900x^2\)

Correct answer is B

Y \(\alpha \frac{1}{x^2} \rightarrow y = \frac{k}{x^2}\)

If x = 3 and y = 100,

then, \(\frac{100}{1} = \frac{k}{3^2}\)

\(\frac{100}{1} = \frac{k}{9}\)

k = 100 x 9 = 900

Substitute 900 for k in

y = \(\frac{k}{x^2}\); y = \(\frac{900}{x^2}\)

= \(yx^2 = 900\)