# The ratio of forks to knives in Mabel's kitchen drawer is 4 to 5. There are 16 forks in the drawer. How many knives are there?

Oct 30, 2016

20 knives

#### Explanation:

Set up the problem as a ratio of forks to knives.

$\left(\text{forks")/("knives}\right) = \frac{4}{5} = \frac{16}{x}$

$\frac{4}{5} = \frac{16}{x}$

Cross multiply

$4 \cdot x = 5 \cdot 16$

$4 x = 80$

Dividide both sides by 4.

$\frac{4 x}{4} = \frac{80}{4}$

$x = 20$ knives

Oct 30, 2016

$4 : 5$

$= 4 \cdot 4 : 5 \cdot 4$

$= 16 : 20$

This means that there are 16 forks and 20 knives.