Mrs. Saffell wants her fifth-grade class to read a variety of books. Her class library has four genres: Classics, Non-fiction, Fiction and Poetry. For each one, she has 10, 15, 25, and 5 different titles respectively. At the end of the first quarter, every student has to submit a list of books they’ve read.

a. If the lists have to contain four books, how many different lists are there?
b. If the lists have to contain four books, at least one of which is non fiction?
c. If the lists have to contain four books no two of which are from the same genre, how many different lists are there?
d. What if the lists have to contain two books from one genre and two books from
another genre, how many different lists are there?
e. If the lists have to contain five books and there is at least one book from each
genre, how many different lists are there?