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.

3,816.

In how many ways can 2 students be selected from a group of 5 students in a debating competition?

A.

25 ways

B.

10 ways

C.

15 ways

D.

20 ways

Correct answer is B

\(In\hspace{1mm} ^{5}C_{2}\hspace{1mm}ways\hspace{1mm}=\frac{5!}{(5-2)!2!}\\=\frac{5!}{3!2!}\\=\frac{5\times4\times3!}{3!\times2\times1}\\=10\hspace{1mm}ways\)

3,817.

find the mean deviation of 1, 2, 3 and 4

A.

2.5

B.

2.0

C.

1.0

D.

1.5

Correct answer is C

X = 1, 2, 3, 4; ∑X = 10
x = ∑X/n = 10/4 = 2.5
X - x = -1.5, -0.5, 0.5, 1.5
lX - xl = 1.5, 0.5, 0.5, 1.5; ∑lX - xl = 4.0
mean deviation = (∑lX - xl)/n
= 4.0/4
= 1.0

3,818.

Some white balls put in a basket containing twelve red balls and sixteen black balls. If the probability of picking a white balls from the baskets is 3/7, how many white balls were introduced?

A.

12

B.

21

C.

28

D.

32

Correct answer is B

Number of white balls = x
Number of red balls = 12
Number of black balls = 16
Total number of balls = 28 + x
P(white balls) = 3/7
But P(white balls) \(= \frac{x}{28+x}\\
= \frac{3}{7} = \frac{x}{28+x}\\
3(28 + x) = 7x\\
84 + 3x = 7x\\
7x - 3x = 84\\
4x = 84\\
x = 21\)

3,819.

Evaluate \(\int_{1}^{3}(x^2 - 1)dx\)

A.

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

B.

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

C.

\(-6\frac{2}{3}\)

D.

\(6\frac{2}{3}\)

Correct answer is D

\(\int_{1}^{3}(x^2 - 1)dx = \left[\frac{1}{3}x^2 - x\right] ^{3}_{1}\\ =(9-3)-(\frac{1}{3}-1)\\ =6-\left(-\frac{2}{3}\right)\\ =6+\frac{2}{3}=6\frac{2}{3}\)

3,820.

Find the derivatives of the function y = 2x\(^2\)(2x - 1) at the point x = -1?

A.

18

B.

16

C.

-4

D.

-6

Correct answer is B

y = 2x\(^2\)(2x - 1)

expand the bracket

y = 4x\(^3\) - 2x\(^2\)


dy/dx = 12x\(^2\) - 4x
at x = -1
dy/dx = 12(-1)\(^2\) - 4(-1)
= 12 + 4
= 16