Question

The ratio of the number of mystery books to the number of science fiction books is 4:3. The ratio of the number of science fiction books to the number of biographies is 4:5. If there are 48 science fiction books, find the total number of books.

Answer 1

Given is the number of science fiction books = 48

Let the number of mystery books be = x

Let the number of biographies be = y

Ratio of the number of mystery books to the number of science fiction books is 4:3 so
`(4)/(3)= (x)/(48)`

=
`3x=48*4`

`x=64`

Ratio of the number of science fiction books to the number of biographies is 4:5 so
`(4)/(5)=(48)/(y)`

=
`4y=5*48`

`y=60`

Hence there are 48 science fiction books, 64 mystery books and 60 biographies.

So total number of books are =
`48+64+60=172`