A dice is toss once. If 1 appears a ball is drawn from box 1. If 2,3,4 appears a ball is drawn in box 2 and If 5,6 appears ball is drawn from box 3. Box 1 contains 5 white, 3 green and 2 red balls. Box 2 contains 1 white, 6 green and 3 red balls while Box 3 contains 3 white, 1 green and 6 red balls.
a. what is the probability that a red ball is drawn?
b. what is the probability that box 2 is selected if a red ball is drawn?
thanks