SOLUTION: One bag contains 4 white balls and 3 black balls and a second bag contains 3 white balls and 5 black balls. One ball is drawn from the first bag and placed unseen in second ba

Question 892094: One bag contains 4 white balls and 3 black balls and a second bag contains 3 white balls and 5 black balls. One ball is drawn from the first bag and placed unseen in second bag. What is the probability that a ball now drawn from the second bag is black?
Answer by robertb(5830) (Show Source): You can put this solution on YOUR website!
Two mutually exclusive cases:
(i) When the ball drawn from the 1st bag is white:
P(1st white and 2nd black) = P(1st white)*P(2nd black|1st white) = = 20/63
(ii) When the ball drawn from the 1st bag is black:
P(1st black and 2nd black) = P(1st black)*P(2nd black|1st black) = = 18/63
==> The probability that a black ball is drawn is .
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