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.

3,831.

A bag contains 5 blacks balls and 3 red balls. Two balls are picked at random without replacement. What is the probability that a black and red balls are picked?

A.

15/28

B.

13/28

C.

5/14

D.

3/14

Correct answer is A

Black balls = 5
Red balls = 3/8
P(B) = 5/8, P(R) = 3/8
P( a Black and a Red) = BR + RB
= (5/8) * (3/7) * (3/8) * (5/7)
= (15/56) + (15/56)
= 30/56
= 15/28

3,832.

Find the number of committees of three that can be formed consisting of two men and one woman from four men and three women

A.

3

B.

6

C.

18

D.

24

Correct answer is C

\(^{4}C_2 \times ^{3}C_1 = \left(\frac{4!}{(4-2)!2!}\right)\times\left(\frac{3!}{(3-1)!1!}\right)\\=\frac{4!}{2!2!}\times \frac{3!}{2!}\\=\frac{4 \times 3 \times 2!}{2 \times 1 \times 2!} \times \frac{3 \times 2!}{2!}\\=18\)

3,833.

If \(^{n}P_{3} - 6(^{n}C_{4}) = 0\), find the value of n.

A.

5

B.

6

C.

7

D.

8

Correct answer is C

\(^{n}P_3 - 6(^{n}C_{4})=0\\\frac{n!}{(n-3)!}-6\left( \frac{n!}{(n-4)!4!}\right)=0\\\frac{n!}{(n-3)!}=6\left(\frac{n!}{(n-4)!4!}\right)\\n!((n-4)!4!)=6n!(n-3)!\\((n-4)!4!)=6(n-3)!\\\frac{(n-4)!}{(n-3)!}=\frac{6}{4!}\\\frac{(n-4)!}{(n-3)(n-4)!}=\frac{6}{4 \times 3\times 2\times 1}\\\frac{1}{(n-3)}=]\frac{1}{4}\\n-3=4\\n=4+3\\n=7\)

3,834.

On a pie chart, there are four sectors of which three angles are 45°, 90° and 135°. If the smallest sector represents N28.00, how much is the largest sector?

A.

N96.00

B.

N84.00

C.

N48.00

D.

N42.00

Correct answer is B

Let the 4th angle be = x
∴ x + 45 + 90 + 135 = 360
x + 270 = 360
x = 360 - 270
x = 90
∴ smallest angle = 45o
45o = N28.00
1o = 28.00/45
135o = (28.00/45) * (135/1)
= N84.00

3,835.

The range of 4, 3, 11, 9, 6, 15, 19, 23, 27, 24,21 and 16 is

A.

16

B.

21

C.

23

D.

24

Correct answer is D

Range = (Highest - Lowest) items
= 27 - 3
= 24