Mary has on her bookshelf 5 novels, 4 biographies, and 8textbooks.
Mary wants to take a fiction and a non-fiction book with her ona short trip.
(a) How many different ways can she do this?
(b) Mary thinks a little and then decides that she wants insteadto take a novel and a biography. How many different ways can she dothis?
(c) On a longer trip Mary decides to take three novels and fournon-fiction books with at least one of the non-fiction books abiography. How many ways are there to make such a selection?
