6.7 A library has five copies of a certain textbook on reserve of which two copies (1 and 2) are hardcover books and the other three (3, 4, and 5) are softcover books. A student examines these books in random order, stopping only when a softcover book has been selected.

a. Display the possible outcomes in a tree diagram.

b. What outcomes are contained in the event A, that exactly one book is examined before the chance experiment terminates?

c. What outcomes are contained in the event C, that the chance experiment terminates with the examination of book 5?