Question
Bag C contains 2 red balls and 2 blue balls, whereas
bag D contains 5 red balls and 5 blue balls. One ball is drawn at random from C and transferred into D. Two balls are now drawn at random from D. Find the probability that both balls are of the same colour.Solution
Required probability
= (2/4) X (6/11) X (5/10) + (2/4) X (5/11) X (4/10) + (2/4) X (5/11) X (4/10) + (2/4) X (6/11) X (5/10) = (2/4) X (30/110) + (2/4) X (20/110) + (2/4) X (20/110) + (2/4) X (30/110) = (60/440) + (40/440) + (40/440) + (60/440) = (200/440) = (5/11)
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