Chapter 16: Probability

Example 2. A bag contains 5 red balls, 8 White balls, 4 green balls and 7 black balls. A ball is drawn at random from the bag. Fine the probability that it is. (i) Black (ii) not green.

Solution:- Red balls = 5

White balls = 8

Green balls = 4

Black balls = 7
Total balls = 24

(i) P (Black balls) = 7/24
(ii) P (not a green ball) = 1- P (green ball)
                                        = 1 - 4/24 = 20/24
                                        = 5/6

Example 3. A card is drawn at random from a pack of 52 playing cards. Find the probability that the card drawn is neither an ace nor a king.

Solution:- P (neither an ace nor a king)

= 1 – p (either an ace or a king)

= 1 – 8/52                            {no. of ace = 4}
                                              {no. of king = 4}
                                                         Total = 8

= (52 – 8)/52

= 44/52

= 11/13