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.

271.

If w varies inversely as \(\frac{uv}{u + v}\) and w = 8 when

u = 2 and v = 6, find a relationship between u, v, w.

A.

uvw = 16(u + v)

B.

16uv = 3w(u + v)

C.

uvw = 12(u + v)

D.

12uvw = u + v

Correct answer is C

W \(\alpha\) \(\frac{\frac{1}{uv}}{u + v}\)

∴ w = \(\frac{\frac{k}{uv}}{u + v}\)

= \(\frac{k(u + v)}{uv}\)

w = \(\frac{k(u + v)}{uv}\)

w = 8, u = 2 and v = 6

8 = \(\frac{k(2 + 6)}{2(6)}\)

= \(\frac{k(8)}{12}\)

k = 12

i.e 12 ( u + v) = uwv

272.

Find the probability that a number selected at random from 41 to 56 is a multiple of 9

A.

\(\frac{1}{8}\)

B.

\(\frac{2}{15}\)

C.

\(\frac{3}{16}\)

D.

\(\frac{7}{8}\)

Correct answer is A

Given from 41 to 56

41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56

The nos multiple of 9 are: 45, 54

P(multiple of 9) = \(\frac{2}{16}\)

= \(\frac{1}{8}\)

273.

Two numbers are removed at random from the numbers 1, 2, 3 and 4. What is the probability that the sum of the numbers removed is even?

A.

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

B.

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

C.

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

D.

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

Correct answer is B

\(\begin{array}{c|c} 1 & 2 & 3 & 4\\\hline 1(1, 1) & (1, 2) & (1, 3) & (1, 4)\\ \hline 2(2, 1) & (2 , 2) & (2, 3) & (2, 4) \\ \hline 3(3, 1) & (3, 2) & (3, 3) & (3, 4)\\ \hline 4(4, 1) & (4, 2) & (4, 3) & (4, 4)\end{array}\)

sample space = 16

sum of nos. removed are (2), 3, (4), 5

3, (4), 5, (6)

(4), 5, (6), 7

(5), 6, 7, (8)

Even nos. = 8 of them

Pr(even sum) = \(\frac{8}{16}\)

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

274.

4, 16, 30, 20, 10, 14 and 26 are represented on a pie chart. Find the sum of the angles of the bisectors representing all numbers equals to or greater than 16

A.

48o

B.

84o

C.

92o

D.

276o

Correct answer is D

Given that 4, 16, 30, 20, 10, 14 and 26

Adding up = 120

nos \(\geq\) 16 are 16 + 30 + 20 + 26 = 92

The requires sum of angles = \(\frac{92}{120}\) x \(\frac{360^o}{1}\)

= 276o

275.

A cylinder pipe, made of metal is 3cm thick.If the internal radius of the pipe is 10cm.Find the volume of metal used in making 3m of the pipe.

A.

153\(\pi\)cm3

B.

207\(\pi\)cm3

C.

15 300\(\pi\)cm3

D.

20 700\(\pi\)cm3

Correct answer is D

Volume of a cylinder = πr\(^2\)h

First convert 3m to cm by multiplying by 100

Volume of External cylinder = \(π \times 13^2 \times 300\)

Volume of Internal cylinder = \(π \times 10^2 \times 300\)

Hence; Volume of External cylinder - Volume of Internal cylinder

Total volume (v) = \(π (169 - 100) \times 300\)

V = \(π \times 69 \times 300\)

V = 20700πcm\(^3\)