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.

1,391.

Simplify (x - 3y)2 - (x + 3y)2

A.

2(x + 3y)

B.

(2x - 3y)

C.

-12xy

D.

6xy

Correct answer is C

(x - 3y)2 - (x + 3y)2 = [(x - 3y) - (x + 3y)]

[(x + 3y + x + 3y)] = [-6y] [2x]

= -12xy

1,392.

The angles of triangle are (x + 10)o, (2x - 40)o and (3x - 90)o. Which of the following accurately describes the triangle?

A.

it is a scalene triangle

B.

it is right angled isosceles triangle

C.

it is an equilateral triangle

D.

It is an isosceles triangle but not right angled

Correct answer is C

(x + 10)o + (2x - 40)o + (3x - 90)o = 180

6x - 120 = 180

6x = 180 + 120

6x = 300

x = \(\frac{300}{6}\)

x = 50

x + 10o = 50o + 10o = 60o

2x - 40 = 2(50o) - 40 = 60o

3x - 90 = 3(50o) - 90o = 60o

Hence, it is an equilateral triangle

1,393.

Simplify; \(\frac{1}{2}\sqrt{32} - \sqrt{18} \sqrt{2}\)

A.

zero

B.

\(\sqrt{2}\)

C.

2\(\sqrt{2}\)

D.

4\(\sqrt{2}\0

Correct answer is A

\(\frac{1}{2}\sqrt{32} - \sqrt{18} \sqrt{2}\) = \(\frac{1}{2} (4\sqrt{2}) - 3\sqrt{2} + \sqrt{2}\)

= 2\(\sqrt{2} - 3\sqrt{2} + \sqrt{2}\)

= 3\(\sqrt{2} - 3\sqrt{2} - 3\sqrt{2}\) = 0

1,394.

A box contains black, white and red identical balls. The probability of picking a black ball at random from the box is \(\frac{3}{10}\) and the probability of picking a white ball at random is \(\frac{2}{5}\). If there are 30 balls in the box, how many of them are red?

A.

3

B.

7

C.

9

D.

12

Correct answer is C

Total no of balls = 30

Let x = no. of red balls

Pr(red) = \(\frac{x}{30}\)

Pr(black) = \(\frac{3}{10} = \frac{9}{30}\)

Pr(white) = \(\frac{2}{5} = \frac{12}{30}\)

No. of black balls = 9

No. of white balls = 12

9 = 12 + x = 30

x = 30 - 21

x = 9

No. of red balls = 9

1,395.

A bucket holds 10 litres of water. How many buckets of water will fill a reservoir of size 8m x 7m x 5m.(1 litre = 1000cm3)`

A.

28

B.

280

C.

2800

D.

28000

Correct answer is D

No. of buckets of water = \(\frac{\text{Capacity of reservoir}}{\text{Capacity of buckets}}\)

= \(\frac{800 \times 700 \times 500}{10 \times 1000}\)

= \(\frac{28000 0000}{10000}\)

= 28000