1. An urn contains 10 white, 15 black and 20 red balls. (a) (8pts) If two balls are randomly withdrawn without replacement, what is the prob- ability that they are the same color? (b) (8pts) Suppose that you are randomly selecting balls with replacement, until a red one is obtained. What is the probability that at most 3 draws are needed? (c) (9pts) Suppose that you pick 1 ball and throw it away. Then pick a second ball and you see that it is black. What is the probability that the first ball was red