Archery. An archer's target has four concentric circles around a bull's-eye. For a certain archer, the probabilities of scoring are as follows: Pr(hit the bull's-eye) = 0.1, Pr(hit first circle, but not bull's-eye) = 0.3. Pr(hit second circle, but no better) = 0.2. Pr(hit third circle, but no better) = 0.2. Pr(hit fourth circle, but no better) = 0.1. Her shots are independent. (a) What is the probability that in two shots she scores a bull's-eye on the first shot, and the third circle on the second shot? (b) What is the probability that in two shots she hits the bull's-eye once, and the third circle once? (c) What is the probability that on any one shot she misses the target entirely?