2. A balanced six-sided die is thrown once. If a 3 appears, a ball is drawn from urn 1; otherwise, a ball is drawn from urn 2. Um 1 contains six red and four White balls. Urn 2 contains four red, three white, and three black balls. a) Find the probability that a red ball is drawn. b) Find the probability that um I was used given that a red ball was drawn