A nationwide award for high school students is given to outstanding students who are sophomores, juniors, or seniors (freshmen are not eligible). Of the award-winners, 64 percent are SENIORS, 21 percent JUNIORS, and 15 percent are SOPHOMORES. NOTE: Your answers below should be entered as decimal numbers. Do not round during intermediate steps. If you round an answer, make sure you do so correctly and keep at least three decimal places. (a) Suppose we select award-winners one at a time and continue selecting until a SENIOR is selected. What is the probability that we will select exactly 3 award-winners