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.

2,711.

\(\begin{array}{c|c}
Numbers & 1 & 2 & 3 & 4 & 5 & 6 \\
\hline
Frequency & 18 & 22 & 20 & 16 & 10 & 14
\end{array}\)

The table above represents the outcome of throwing a die 100 times. What is the probability of obtaining at least a 4?

A.

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

B.

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

C.

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

D.

\(\frac{3}{4}\)

Correct answer is C

Let E demote the event of obtaining at least a 4
Then n(E) = 16 + 10 + 14 = 40

Hence, prob (E) = \(\frac{n(E)}{n(S)}\)

\( = \frac{40}{100}\)

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

2,712.

In how many ways can a team of 3 girls be selected from 7 girls?

A.

\(\frac{7!}{3!}\)

B.

\(\frac{7!}{4!}\)

C.

\(\frac{7!}{3!4!}\)

D.

\(\frac{7!}{2!5!}\)

Correct answer is C

A team of 2 girls can be selected from 7 girls in \(^7C_3\)

\( = \frac{7!}{(7 - 3)! 3!}\)

\( = \frac{7!}{4! 3!} ways\)

2,713.

Find the standard deviation of 5, 4, 3, 2, 1

A.

\(\sqrt{2}\)

B.

\(\sqrt{3}\)

C.

\(\sqrt{6}\)

D.

\(\sqrt{10}\)

Correct answer is A

Mean x = \(\frac{\sum x}{n}\)

\( = \frac{5 + 4 + 3 + 2 + 1}{5}\)

\( = \frac{15}{5}\)

= 3

\(\begin{array}{c|c}
x & d = x - 3 & d^2 \\
\hline
5 & 2 & 4 \\
4 & 1 & 1 \\
3 & 0 & 0 \\
2 & -1 & 1 \\
1 & -2 & 4 \\
\hline
& & \sum d^2 + 10
\end{array}\)

Hence, standard deviation;

\( = \sqrt{\frac{\sum d^2}{n}} = \sqrt{\frac{10}{5}}\)


\( = \sqrt{2}\)

2,714.

Find the median of 5,9,1,10,3,8,9,2,4,5,5,5,7,3 and 6

A.

6

B.

5

C.

4

D.

3

Correct answer is B

First arrange the numbers in order of magnitude; 1,2,3,3,4,5,5,5,5,6,7,8,9,9,10 Hence the median = 5