story problem

Question

The recipe for a holiday punch calls for 7 cups of fruit drink and 3 cups of ginger ale. Suppose you want to make as much punch as you can using all of the fruit drink you have, which is 31 cups. How many cups of ginger ale would you need?

Answer 1

If we use 31 cups of fruit drink, then we calculate ginger ale = 31 (3/7) = 13 cups
To help visualize:
3 ginger ale / 7 fruit drink = 13 ginger ale / 31 fruit drink