Two boxes contain colored balls. Box 1 contains 4 blue, 5 green and 3 red balls. Box 2 contains 6 blue, 2 green and 3 red balls. A ball is selected at random from box 1 and transferred to box 2. A ball is then selected at random from box 2. If the ball selected from box 2 is green, what is the probability that the ball transferred from box 1 was: (a) red? (b) blue?