A college library has four copies of a certain book; the copies are numbered 1, 2, 3, and 4. Two of these are selected at random. The first selected book is placed on 2-hour reserve, and the second book can be checked out overnight.
a. Construct a tree diagram to display the 12 outcomes in the sample space.
b. Let A denote the event that at least one of the books selected is an even-numbered copy. What outcomes are in A?
c. Suppose that copies 1 and 2 are hardcover books, whereas copies 3 and 4 are softcover books. Let B denote the event that exactly one of the copies selected is a hardcover book. What outcomes are contained in B?