Probability Questions

1.      A bag contains 6 black and 8 white balls. One ball is drawn at random. What is the probability that the ball drawn is white?

(a) 3/4                               (b) 4/7

(c) 1/8                               (d) 3/7

2.      A box contains 5 green, 4 yellow and 3 white marbles. Three marbles are drawn at random. What is the probability that all they are not of the same colour?

(a) 3/44                             (b) 3/55

(c) 52/55                           (d) 41/44

3.      A bag contains 4 white, 5 red and 6 blue balls. Three balls are drawn at random from the bag. The probability that all of them are red, is:

(a) 1/22                             (b) 3/22

(c) 2/91                             (d) 2/77

4.      A bag contains 6 white and 4 red balls. Three balls are drawn at random. What is the probability that one ball is red and the other two are white?

(a) 1/2                               (b) 1/12

(c) 3/10                             (d) 7/12

5.      A bag contains 2 red, 3 green and 2 blue balls. Two balls are drawn at random. What is the probability that none of the balls drawn is blue?

(a) 10/21                           (b) 11/21

(c) 2/7                               (d) 5/7

6.      In a box there are 8 red, 7 blue and 6 green balls, one ball is picked up randomly. What is the probability that it is neither red nor green?

(a) 2/3                               (b) 3/4

(c) 7/19                             (d) 8/21                        (e) 9/21

7.      A box contains 10 black and 10 white balls. The probability of drawing two balls of the same colour is

(a) 9/19                             (b) 9/38

(c) 10/19                           (d) 5/19

8.    A box contains 4 red balls, 5 green balls and 6 white balls. A ball is drawn at random from the box. What is the probability that the ball drawn is either red or green?

(a) 2/5                               (b) 3/5

(c) 1/5                               (d) 7/15

9.      In a class, there are 15 boys and 10 girls. Three students are selected at random. The probability that 1 girl and 2 boys are selected is:

(a) 21/46                           (b) 25/ 117

(c) 1/50                             (d) 3/25

10.   Four persons are chosen at random from a group of 3 men, 2 women and 4 children. The chance that exactly 2 of them are children, is:

(a) 1/9                               (b) 1/5

(c) 1/12                             (d) 10/21

                                                     Answers

1	b	6	d
2	d	7	a
3	c	8	b
4	a	9	a
5	a	10	d