There are 13 books on a shelf. 8 of these books are new.

(a) What is the ratio of all books to used books?

(b) What is the ratio of used books to new books?

13-8 = 5 so 8 new, 5 used

A. all to used 13:5

B. used to new 5:8

Well we can find out how many used books there are by subtracting 8 from 13 which gives us 5. Then we put that in a ratio for all to used it would be 13:5 or 13/5

Used to new would be 5:8 or 5/8