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.

2,236.

Evaluate 2700 000 x 0.03 ÷ 18 000

A.

4.5 x 100

B.

4.5 x 101

C.

4.5 x 102

D.

4.5 x 103

Correct answer is A

\(2700000 \times 0.03 \div 18000\)

= \(\frac{2700000 \times 0.03}{18000}\)

= \(\frac{81000}{18000} = 4.5 \times 10^{0}\)

2,237.

Which of the following is in descending order?

A.

\(\frac{9}{10} \frac{4}{5} \frac{3}{4} \frac{17}{20}\)

B.

\(\frac{4}{5} \frac{9}{10} \frac{3}{4} \frac{17}{20}\)

C.

\(\frac{9}{10} \frac{17}{20} \frac{4}{5} \frac{3}{4}\)

D.

\(\frac{4}{5} \frac{9}{10} \frac{17}{20} \frac{3}{4}\)

Correct answer is C

\(\frac{9}{10} \frac{4}{5} \frac{3}{4} \frac{17}{20}\) = \(\frac{18, 16, 15, 17}{20}\)

\(\frac{4}{5} \frac{9}{10} \frac{3}{4} \frac{17}{20}\) = \(\frac{16, 18, 15, 17}{20}\)

\(\frac{9}{10} \frac{17}{20} \frac{4}{5} \frac{3}{4}\) = \(\frac{18, 17, 16, 15}{20}\)

∴ \(\frac{9}{10}; \frac{17}{20}; \frac{4}{5}; \frac{3}{4}\) is in descending order.

2,238.

Find the probability that a number selected at random from 41 to 56 is a multiply of 9

A.

\(\frac{1}{8}\)

B.

\(\frac{2}{15}\)

C.

\(\frac{3}{16}\)

D.

\(\frac{7}{8}\)

Correct answer is A

Given from 41 to 56

41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56

The nos multiple of 9 are: 45, 54

P(multiple of 9) = \(\frac{2}{16}\)

= \(\frac{1}{8}\)

2,239.

Two numbers are removed at random from the numbers 1, 2, 3 and 4. What is the probability that the sum of the numbers removed is even?

A.

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

B.

\(\frac{2}{15}\)

C.

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

D.

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

Correct answer is C

\(\begin{array}{c|c} 1 & 2 & 3 & 4\\\hline 1(1, 1) & (1, 2) & (1, 3) & (1, 4)\\ \hline 2(2, 1) & (2 , 2) & (2, 3) & (2, 4) \\ \hline 3(3, 1) & (3, 2) & (3, 3) & (3, 4)\\ \hline 4(4, 1) & (4, 2) & (4, 3) & (4, 4)\end{array}\)

sample space = 16

sum of nos. removed are (2), 3, (4), 5

3, (4), 5, (6)

(4), 5, (6), 7

(5), 6, 7, (8)

Even nos. = 8 of them

Pr(even sum) = \(\frac{8}{16}\)

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

2,240.

Below are the scores of a group of students in a test
\(\begin{array}{c|c} Scores & 1 & 2 & 3 & 4 & 5 & 6 \\ \hline \text{No. of students} & 1 & 4 & 5 & 6 & x & 2\end{array}\)
If the average scores is 3.5, find the value of x

A.

1

B.

2

C.

3

D.

4

Correct answer is B

\(\begin{array}{c|c} Scores & 1 & 2 & 3 & 4 & 5 & 6 \\ \hline \text{No. of students} & 1 & 4 & 5 & 6 & x & 2\end{array}\)
Average = 3.5

3.5 = \(\frac{(1 \times 1) + (2 \times 4) + (3 \times 5) + (4 \times 6) + 5x + (6 \times 2)}{1 + 4 + 5 + 6 + x + 2}\)

\(\frac{3.5}{1}\) = \(\frac{1 + 8 + 15 + 24 + 5x + 12}{18 + x}\)

\(\frac{3.5}{1}\) = \(\frac{60 + 5x}{18 + x}\)

60 + 5x = 3.5(18 \(\div\) x)

60 + 5x = = 63 + 1.5x

5x - 1.5x = 63 - 60

1.5x = 3

x = \(\frac{3}{1.5}\)

\(\frac{30}{15}\) = 2