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.

2,541.

The identity element with respect to the multiplication shown in the diagram below is \(\begin{array}{c|c} \otimes & p & p & r & s \\ \hline p & r & p & r & p
\\ q & p & q & r & s\\ r & r & r & r & r\\ s & q & s & r & q\end{array}\)

A.

p

B.

q

C.

r

D.

s

Correct answer is B

The identity element (e) under an operation, say \(\otimes\), is the element such that for any given element under the operation, say a,

\(a \otimes e = e \otimes a = a\)

From the table, q is the identity element.

\(p \otimes q = q \otimes p = p\)

Same as all through.

2,542.

The sum of the first three terms of a geometric progression is half its sum to infinity. Find the positive common ratio of the progression.

A.

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

B.

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

C.

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

D.

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

Correct answer is B

Let the G.p be a, ar, ar2, S3 = \(\frac{1}{2}\)S

a + ar + ar2 = \(\frac{1}{2}\)(\(\frac{a}{1 - r}\))

2(1 + r + r)(r - 1) = 1

= 2r3 = 3

= r3 = \(\frac{3}{2}\)

r(\(\frac{3}{2}\))\(\frac{1}{3}\) = \(\sqrt{\frac{3}{2}}\)

2,543.

If p + 1, 2P - 10, 1 - 4p2are three consecutive terms of an arithmetic progression, find the possible values of p

A.

-4, 2

B.

-3, \(\frac{4}{11}\)

C.

-\(\frac{4}{11}\), 2

D.

5, -3

Correct answer is C

2p - 10 = \(\frac{p + 1 + 1 - 4P^2}{2}\) (Arithmetic mean)

= 2(2p - 100 = p + 2 - 4P2)

= 4p - 20 = p + 2 - 4p2

= 4p2 + 3p - 22 = 0

= (p - 2)(4p + 11) = 0

∴ p = 2 or -\(\frac{4}{11}\)

2,544.

If x is a positive real number, find the range of values for which \(\frac{1}{3x}\) + \(\frac{1}{2}\) > \(\frac{1}{4x}\)

A.

0 > -\(\frac{1}{6}\)

B.

x > 0

C.

0 < x < 4

D.

0 < x < \(\frac{1}{6}\)

Correct answer is D

\(\frac{1}{3x}\) + \(\frac{1}{2}\) > \(\frac{1}{4x}\)

= \(\frac{2 + 3x}{6x}\) > \(\frac{1}{4x}\)

= 4(2 + 3x) > 6x = 12x2 - 2x = 0

= 2x(6x - 1) > 0 = x(6x - 1) > 0

Case 1 (-, -) = x < 0, 6x -1 < 0

= x < 0, x < \(\frac{1}{6}\) = x < \(\frac{1}{6}\) (solution)

Case 2 (+, +) = x > 0, 6x -1 > 0 = x > 0, x > \(\frac{1}{6}\)

Combining solutions in cases(1) and (2)

= x > 0, x < \(\frac{1}{6}\) = 0 < x < \(\frac{1}{6}\)

2,545.

Express in partial fractions \(\frac{11x + 2}{6x^2 - x - 1}\)

A.

\(\frac{1}{3x - 1}\) + \(\frac{3}{2x + 1}\)

B.

\(\frac{3}{3x + 1}\) - \(\frac{1}{2x - 1}\)

C.

\(\frac{3}{3x + 1}\) - \(\frac{1}{2x - 1}\)

D.

\(\frac{1}{3x + 1}\) + \(\frac{3}{2x - 1}\)

Correct answer is D

\(\frac{11x + 2}{6x^2 - x - 1}\) = \(\frac{11x + 2}{(3x + 1)(2x - 1)}\)

= \(\frac{A}{3x + 1}\) + \(\frac{B}{2x - 1}\)

11x + 2 = A(2x - 1) + B(3x + 1)

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

\(\frac{15}{2} = \frac{5}{2}B\)

B = 3.

put x = \(-\frac{1}{3}\)

\(-\frac{5}{3} = \frac{-5}{3}\)A \(\implies\) A = 1

∴ \(\frac{11x +2}{6x^2 - x - 1}\) = \(\frac{1}{3x + 1}\) + \(\frac{3}{2x - 1}\)