# A cleaning solution label says to mix 1 part solution to 5 parts water. How many gallons of solution should be mixed with 20 gallons of water?

4

Explanation

Set up a proportion and solve.

$$\frac{\text{solution}}{\text{water}} = \frac{1}{5}=\frac{x}{5}$$
$$5x = 20$$

$$x = 4$$
So, 4 gallons of solution should be mixed with 20 gallons of water.