The ratio of cups of orange juice concentrate to water in a punch recipe is 2 : 5. If Geoffrey used 20 cups of water, how many cups of orange juice concentrate did he use?

8 cups

Step-by-step explanation:

Let the cups of orange juice concentrate that he used be represented by x.

Therefore, based on the information, we can form an equation which will be:

2/5 = x/20

Cross multiply

5 × x = 2 × 20

5x = 40

x = 40/5

x = 8

Therefore, he used 8 cups of orange juice concentrate.