Question

A bag contains 5 black, 7 red and 3 white balls. A ball is drawn from the bag at random. Find the probability that the ball drawn is: (i) red (ii) black or white (iii) not black Select the correct answer from above options

Answer 1

Given: A bag contains 7 red, 5 black and 3 white balls and a ball is drawn at random Required to find: Probability of getting a (i) Red ball (ii) Black or white ball (iii) Not black ball Total number of balls 7 + 5 + 3 = 15 (i) Total number red balls is 7 We know that, Probability = Number of favourable outcomes/ Total number of outcomes Thus, the probability of drawing a red ball = 7/15 (ii) Total number of black or white balls is 5 + 3 = 8 We know that, Probability = Number of favourable outcomes/ Total number of outcomes Thus, the probability of drawing white or black ball = 8/15 (iii) Total number of black balls is 5 We know that, Probability = Number of favourable outcomes/ Total number of outcomes Thus, the probability of drawing black ball P(E) = 5/15 = 1/3 But, this is not what is required. And, we know that sum of probability of occurrence of an event and probability of non-occurrence of an event is 1 Thus, the probability of drawing a card that is not black is 2/3.