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.

3,851.

x varies directly as the product of u and v and inversely as their sum. If x = 3 when u = 3 and v = 1, what is the value of x if u = 3 and v = 3?

A.

3

B.

4

C.

6

D.

9

Correct answer is C

\(x\propto \frac{uv}{u+v}\\x = \frac{kuv}{u+v}\\K = \frac{x(u+v)}{uv}\\\frac{3(3+1)}{3\times1}\\\frac{3\times4}{3}\\k = 4\\x=\frac{4uv}{u+v}\\x=\frac{4\times 3\times3}{3+3}\\x=\frac{36}{6}\\x=6\)

3,852.

Given:
U = {Even numbers between 0 and 30}
P = {Multiples of 6 between 0 and 30}
Q = {Multiples of 4 between 0 and 30}
Find (P∪Q)c

A.

{2, 10, 14, 22, 26}

B.

{0, 10, 14, 22, 26}

C.

{2,4, 14, 18, 26}

D.

{0, 2, 6, 22, 26}

Correct answer is A

U = {2,4,6,8,10,12,14,16,18,20,22,24,26,28,30}
P = {6,12,18,24,30}
Q = {4,8,12,16,20,24,28}
P∪Q = {4,6,8,12,16,18,20,24,28,30}
(P∪Q)c = {2,10,14,22,26}

3,853.

Find the range of 1/6, 1/3, 3/2, 2/3, 8/9 and 4/3

A.

3/4

B.

5/6

C.

7/6

D.

4/3

Correct answer is D

1/6, 1/3, 3/2, 2/3, 8/9 and 4/3
L.C.M of the denominators = 36
The fraction now becomes
6/36, 12/36, 54/36, 24/36, 32/36 and 48/36
Highest fraction = 54/36
Lowest fraction = 6/36
Range = Highest - Lowest
(54/36) - (6/36)
= 48/36
= 4/3

3,854.

Find the number of ways of selecting 8 subjects from 12 subjects for an examination

A.

490

B.

495

C.

496

D.

498

Correct answer is B

Combination is the number (n) of ways of selecting a number of (m) of objects from n
\(^{12}C_{8}\frac{12!}{8!(12-8)!}\\=\frac{12!}{8!4!}\\\frac{(12\times 11\times 10\times 9\times 8\times 7\times 6\times 5\times 4\times 3\times 2\times 1)}{8\times 7\times 6\times 5\times 4\times 3\times 2\times 1}\\After\hspace{1mm} cancelling \hspace{1mm}out \hspace{1mm}we\hspace{1mm} have\\11\times 5\times 9 = 495 \)

3,855.

Find the variance of 2, 6, 8, 6, 2 and 6

A.

6

B.

5

C.

√6

D.

√5

Correct answer is B

mean of X = x = (2+6+8+6+2+6)/6 = 30/6 = 5
X → 2,6,8,6,2,6
X - x = -3, 1, 3, 1, 3, 1
(X - x)2 = 9, 1, 9, 1, 9, 1
∑(X-x) = 9+1+9+1+9+1 = 30
Variance = ∑(X-x)2/n = 30/6 = 5