Question

A bag contains 4 white balls, 5 red balls, 2 black balls and 4 green balls. A ball is drawn at random from the bag. Find the probability that it is (i) black, (ii) not green, (iii) red or white, (iv) neither red nor green.

Answer 1

Total number of balls = 15

(i) Number of black balls = 2

∴  P(getting a black ball) =`"Number of favourable outcomes"/"Number of all possible outcomes" 2/15`

Thus, the probability of getting a black ball is `2/15`

(ii) Number of balls which are not green = 4 + 5 + 2 = 11

∴  P(getting a ball which is not green) =`"Number of  favourable outcomes "/"Number of all possible outcome" = 11/15`

Thus, the probability of getting a ball which is not green is `11/15.`

(iii) Number of balls which are either red or white = 4 + 5 = 9

∴  P(getting a ball which is red or white) = `"Number of favourable outcomes"/"Number of all possible outcomes" = 9/15`

Thus, the probability of getting a ball which is red or white is = 6

Thus, the probability of getting a ball which is red or white is `3/5`.

(iv) Number of balls which are neither red nor green = 4 + 2 = 6

∴  P(getting a ball which is neither red nor green) = `"Number of favourable outcome"/"Number of all possible  outcomes" = 6/15 = 2/5`

Thus, the probability of getting a ball which is neither red nor green is `2/5`.