Amy has six books from the Statistics is Fun series. She plans on bringing two of the six books with her in a road trip. (a) How many different ways

Amy has six books from the Statistics is Fun series. She plans on bringing two of the six books with her in a road trip.

(a) How many different ways can the two books be selected?

(b) Please describe the method used and the reason why it is appropriate for answering the question.