Question

A bag contains 5 red, 8 white and 7 black balls. A ball is drawn at random from the bag. Find the probability that the drawn ball is (i) red or white (ii) not black (iii) neither white nor black. Select the correct answer from above options

Answer 1

Total number of possible outcomes = 20 (5 red, 8 white & 7 black} (i) Let E = event of drawing a red or white ball No. of favourable outcomes = 13 (5 red + 8 white) Probability, P(E) = Number of favourable outcomes/ Total number of outcomes P(E) = 13/20 (ii) Let E = event of getting a black ball No. of favourable outcomes =7 (7 black balls) Probability, P(E) = Number of favourable outcomes/ Total number of outcomes P(E) = 7/20 ¯ E = Event of not getting black ball (iii) Let E = Event of getting neither a white nor a black ball No. of favourable outcomes = 20 – 8 – 7 = 5(total balls – no. of white balls – no. of black balls) Probability, P(E) = Number of favourable outcomes/ Total number of outcomes P(E) = 5/20 = 1/4