In survey of undergraduate library usage, it was found that 88% of seniors, 62% of juniors, 48% of sophomores, and 40% of freshmen use the library frequently. Suppose that 17% of the undergraduates are seniors while the corresponding percentages for juniors, sophomores, and freshmen are 18%, 21%, and 44% respectively.
What percent of the students use the library frequently?
Suppose you see a student use the library everyday. What is the probability that this student is a freshman?