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.

2,321.

Two perfect dice are thrown together, Determine the probability of obtaining a total score of 8

A.

\(\frac{1}{12}\)

B.

\(\frac{5}{36}\)

C.

\(\frac{1}{6}\)

D.

\(\frac{7}{36}\)

Correct answer is B

\(\begin{array}{c|c} & & 1 & 2 & 3 & 4 & 5 & 6 \\ \hline a & 1 & 1, 1 & 1, 2 & 1, 3 & 1, 4 & 1, 5 & 1, 6\\\hline & 2 & 1,1 & 2, 2 & 2, 3 & 2, 4 & 2, 5 & 2, 6 \\\hline B & 3 & 3, 1 & 3, 2 & 3, 3 & 3, 4 & 3, 5 & 3, 6\\\hline & 4 & 4 , 1 & 4, 2 & 4, 3 & 4, 4 & 4, 5 & 4, 6\\\hline Die & 5 & 5, 1 & 5, 2 & 5, 3 & 5, 4 & 5, 5 & 5, 6 \\\hline & 6 & 6, 1 & 6, 2 & 6, 3 & 6, 4 & 6, 5 & 6, 6\end{array}\)

Probability of obtaining total score of 8 = \(\frac{5}{36}\)

2,322.

If the scores of 3 students in a test are 5, 6 and 7, find the standard deviation of their scores

A.

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

B.

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

C.

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

D.

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

Correct answer is C

(x) = \(\frac{5 + 6 + 7}{3}\)

= \(\frac{18}{3}\)

= 6

\(\begin{array}{c|c} scores(X) & \text{d = (x - x) deviation} & (deviation)^2\\\hline 5 & 5 - 6 & 1\\ 6 & 6 - 6 & 0 \\ 7 & 7 - 6 & 1\\ \hline & & 2\end{array}\)

S.D \(\sqrt{\frac{\sum d^2}{n}}\) where d = deviation = (x - x)

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

2,324.

\(\begin{array}{c|c} x & 2 & 4 & 6 & 8\\ \hline f & 4 & y & 6 & 5 \end{array}\)
If the mean of the above frequency distribution is 5.2, find y

A.

2, 1

B.

1, 2

C.

1, 5

D.

5, 2

Correct answer is C

Mean \(\bar{x}\) = \(\frac{\sum fx}{\sum f}\)

= \(\frac{5.2}{1}\)

= \(\frac{8 + 4y + 36 + 40}{4 + y + 6 + 5}\)

= \(\frac{5.2}{1}\)

= \(\frac{84 + 4y}{15 + y}\)

= 5.2(15 + y)

= 84 + 4y

= 5.2 x 15 + 5.2y

= 84 + 4y

= 78 + 5.2y

= 84 = 4y

= 5.2y - 4y

= 84 - 78

1.2y = 6

y = \(\frac{6}{1.2}\)

= \(\frac{60}{12}\)

= 5