Dustin is mixing concrete. A formula for concrete calls for 3/8 gal of water. Dustin wants to make 7/9 more concrete than the formula creates. How much water should Dustin use? Simplify your answer.

We can use a ratio to solve this question. Lets refer to the amount formed by the formula as a serving

1 serving needs 3/8 gal

We want to create 7/9 servings extra, so

1 + 7/9 = 16/7

1 : 3/8

16/7 : x

1 / (3/8) = (16/7) / x

8 / 3 = 16x / 7

x = 7/6

He needs to use 7/6 gallons of water.