Answer and Explanation : Probability Questions For Bank Clerk Prelims : 01

Probability Questions: 01

 

Answers & Explanation:

1) Answer: D

Total number of balls = 10 + x

Required probability

= > 6/(10 + x) = 2/5

= > 10 + x = 15

= > x = 5

Total number of balls in the basket = 10 + 5 = 15 balls

2) Answer: B

Total event=(HHH, HHT, HTH, THH, THT, HTT, TTH, TTT)

=8

Possible ways =(THT, HTT, TTH)=3

Required probability=3/8

3) Answer: A

Total event=(1, 2, 3, 4, 5, 6)

Possibility of getting Prime number=(2, 3, 5)

Required probability=3/6=1/2

4) Answer: D

The number of kings in the pack=4

Total number of cards=52

Required probability=4C₂ /52C₂ = (4 * 3)/(52 * 51)

=1/221

5) Answer: B

Required probability=4C₂/7C₂

= (4 * 3)/(7 * 6)

=2/7

6) Answer: A

Required probability=5C₂ / 9C₂

= 20/72

= 5/18

7) Answer: C

Required probability = (4C₂ + 3C₂ )/13C₂

= 3/26

8) Answer: A

Total number of cards = 52

Number of jack = 4

Number of queen = 4

Required probability = 1 – (4/52 + 4/52)

= 44/52

= 11/13

9) Answer: B

Total fruits = 4 + 3 = 7

Required probability = 4C₂/7C₂

= 4 * 3/7 * 6

= 2/7

10) Answer: D

Total balls = 30 Total prime numbers between 1 to 30 = 2, 3, 5, 7, 11, 13, 17, 19, 23, 29 = 10 Total perfect square = 1, 4, 9, 16, 25 = 5

Probability of selecting first ball = 10/30 = 1/3

Probability of selecting second ball = 5/30 = 1/6

Therefore, probability = (1/3) * (1/6) = 1/18