Two bags each contains 91 balls. In each bag, there are 3 red balls, 1 white and the rest blue.
(i) One ball is drawn from the first bag. Find the probability that it is not blue.
(ii) One ball is drawn from the second bag. Find the probability that it is blue.
(iii) One ball is drawn from each bag. Find the probability that the two balls are
(a) both blue,
(b) each of a different colour.
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Answer:
In each bag, there are 3 red balls, 1 white and 87 blue.
(i) P(ball is not blue) = 4/91
(ii) P(ball is blue) = 87/91
(iii)
(a) P(both balls are blue) = 87/91 * 87/91
= 7569/8281
(b) P(both balls same colour)
= P(both red) + P(both white) + P(both blue)
= 3/91 * 3/91 + 1/91 * 1/91 + 7569/91
= 7579/8281
P(both balls are different colour) = 1 - P(both balls same colour)
= 1 - 7579/8281
= 702/8281
