On a Saturday a library checked out 66 books and 18 of the books were fiction what is the fraction of nonfiction books to fiction books checked out

18 out of 66 of the books are fiction

To find the number of nonfiction, subtract 18 from 66

66 - 18 = 48 nonfiction books

The question asks for nonfiction to fiction books in a ratio

Nonfiction : Fiction

Replace the words with their values

48 : 18

This ratio can be simplified as both numbers share a highest common factor of 6

48/6 = 8

18/6 = 3

The final ratio is

8 : 3