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 $\frac{4}{3}= \frac{x}{48}$

=$3x=48\times4$

$x=64$

Ratio of the number of science fiction books to the number of biographies is 4:5 so $\frac{4}{5}=\frac{48}{y}$

=$4y=5\times48$

$y=60$

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

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