Question

There are 13 books on a shelf. Of these books are new. 9 The rest of them are used. (a) What is the ratio of used books to new books? (b) What is the ratio of all books on the shelf to used books?

Answer 1

a) The ratio of used books to new books is of
`(9)/(4)`.

b) The ratio of all books on the shelf to used books is of
`(13)/(9)`

Explanation:

Ratio of a to b:

The ratio of a to b is given by:

`(a)/(b)`

Ratio of b to a:

The ratio of b to a is given by:

`(b)/(a)`

In this question:

13 books, 9 used, 4 new.

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

9 used, 4 new. So

The ratio of used books to new books is of
`(9)/(4)`.

(b) What is the ratio of all books on the shelf to used books?

13 books on the shelf, 9 used. So

The ratio of all books on the shelf to used books is of
`(13)/(9)`