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.

2,566.

Find the values of x and y respectively if
\(\begin{pmatrix} 1 & 0 \\ -1 & -1\\ 2 & 2 \end{pmatrix}\) + \(\begin{pmatrix} x & 1 \\ -1 & 0\\ y & -2 \end{pmatrix}\) = \(\begin{pmatrix} -2 & 1 \\ -2 & -1\\ -3 & 0 \end{pmatrix}\)

A.

-3, -2

B.

-5, -3

C.

-2, -5

D.

-3, -5

Correct answer is D

\(\begin{pmatrix} 1 & 0 \\ -1 & -1\\ 2 & 2 \end{pmatrix}\) + \(\begin{pmatrix} x & 1 \\ -1 & 0\\ y & -2 \end{pmatrix}\) = \(\begin{pmatrix} -2 & 1 \\ -2 & -1\\ -3 & 0 \end{pmatrix}\)

therefore, (x, y) = (-3, -5) respectively

2,567.

What value of x will make the function x(4 - x) a maximum?

A.

4

B.

3

C.

2

D.

1

Correct answer is C

x(4 - x)

4x - x2

\(\frac{dy}{dx}\) = 4 - 2x

\(\frac{dy}{dx}\) = 0

2x = 4

x = \(\frac{4}{2}\)

= 2

2,568.

Determine the value of x for which (x2 - 1)>0

A.

x < -1 or x > 1

B.

-1 < x < 1

C.

x > 0

D.

x < -1

Correct answer is A

x(x - 1) > 0 x < -1 or x > 1

2,569.

W is directly proportional to U. If W = 5 when U = 3, find U when W = \(\frac{2}{7}\)

A.

\(\frac{6}{35}\)

B.

\(\frac{10}{21}\)

C.

\(\frac{21}{10}\)

D.

\(\frac{35}{6}\)

Correct answer is A

W \(\alpha\) U

W = ku

u = \(\frac{w}{k}\); \(\frac{2}{7}\) x \(\frac{3}{5}\)

= \(\frac{6}{35}\)

2,570.

Find the standard deviation of 2, 3, 5 and 6

A.

√6

B.

√10

C.

√\(\frac{2}{5}\)

D.

√\(\frac{5}{2}\)

Correct answer is D

\(\begin{array}& x & x - \bar{x} & (x - \bar{x})^2 \\2 & -2 & 4 \\ 3 & -1 & 1 \\ 5 & 1 & 1 \\ 6 & 2 & 4\\ \hline \sum x = 16 & & \sum (x - \bar{x}^2) = 10 \end{array}\)
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\(\bar{x}\) = \(\frac{\sum x }{N}\)

= \(\frac{16}{4}\)

= 4

S = \(\sqrt{\frac {(x - \bar{x})^2}{N}}\)

= \(\sqrt{\frac {(10)}{4}}\)

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