Your school librarian has asked your class for some help on the purchase of some new bookcases with two shelves each. She has
300 new books she needs to shelve. One half of the books are half
an inch thick. One third of them are one fourth of an inch thick,
and the rest are three fourths of an inch thick. Her shelves are
30 inches long. How many bookcases should she buy?

An oil exploration company currently has two active projects, one in asia and the other in europe. let a be the event that the asian project is successful and b be the event that the european project is successful. suppose that a and b are independent events with p(a) = 0.2 and p(b) = 0.8. (a) if the asian project is not successful, what is the probability that the european project is also not successful? (b) what is the probability that at least one of the two projects will be successful? (c) given that at least one of the two projects is successful, what is the probability that only the asian project is successful? (round your answer to three decimal places.)