MATHS
posted by RS .
Mrs.Koh purchased new books for the school library, of which 6 were Mathematics books, 7 were Science books, 10 were Music books, 3 were Art books, and 4 were
social studies books. All of these books were different. She picked a book from each subject to display in a row on a self. How many different possible displays could there be?

number of choices for a row
= 6x7x10x3x4 = 5040
now each of these can be arranged in 5! ways
so number of possible different displays = 5!(5040)
= 604800 
there are 8 boxes on the shelf. 2 of the books are fiction. the rest are nonfiction what fraction of the books are fiction

In a bookcase, there are 7 fiction books for every 4 nonfiction books. There are 33 books in the bookcase. How many nonfiction books are in the bookcase?