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.

2,441.

Let p be a probability function on set S, where S = (a1, a2, a3, a4). Find P(a1) if P(a2) = \(\frac{1}{3}\), p(a3) = \(\frac{1}{6}\) and p(a4) = \(\frac{1}{5}\)

A.

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

B.

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

C.

\(\frac{1}{3}\)

D.

\(\frac{3}{10}\)

Correct answer is D

No explanation has been provided for this answer.

2,444.

The variance of the scores 1, 2, 3, 4, 5 is

A.

1, 2

B.

1, 4

C.

2.0

D.

3.0

Correct answer is C

\(x\) 1 2 3 4 5 sum =15
\(x - \bar{x}\) -2 -1 0 1 2  
\((x - \bar{x})^{2}\) 4 1 0 1 4 10

Mean = \(\frac{15}{5} = 3\)

\(Variance = \frac{\sum (x - \bar{x})^{2}}{n}\)

= \(\frac{10}{5}\)

= \(2.0\)

 

2,445.

\(\begin{array}{c|c} class& 1 - 3 & 4 - 6 & 7 - 9\\ \hline Frequency & 5 & 8 & 5\end{array}\)
Find the standard deviation of the data using the table above

A.

5

B.

\(\sqrt{6}\)

C.

\(\frac{5}{3}\)

D.

\(\sqrt{5}\)

Correct answer is D

\(\begin{array}{c|c} \text{class intervals} & Fre(F) & \text{class-marks(x)} & Fx & (x - x)& (x - x)^2 & F(x - x)^2 \\ \hline 1 - 3 & 5 & 2 & 10 & -3 & 9 & 45\\ 4 - 6 & 8 & 5 & 40 & 0 & 0 & 0 \\ 7 - 9 & 5 & 8 & 40 & 3 & 9 & 45 \\ \hline & 18 & & 90 & & & 90 \end{array}\)

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

= \(\frac{90}{18}\)

= 5

S.D = \(\frac{\sum f(x - x)^2}{\sum f}\)

= \(\frac{90}{18}\)

= \(\sqrt{5}\)