Question

Ian makes 7 ½ quarts of fruit punch using 3 different juices. The juices he used are listed.  3 ¼ quarts of blueberry juice  1 1/3 quarts of pineapple juice  W quarts of watermelon juice How many quarts of watermelon juice, W, did Ian use to make the fruit punch?

Answer 1

A total of 7 1/2 quarts of fruit punch coming from 3 fruits: blueberry, pineapple and watermelon which contributed 3 1/4 quarts, 1 1/3 quarts, and W, respectively.

Let's make the equation.
7 1/2 = 3 1/4 + 1 1/3 + W
W = 7 1/2 - 3 1/4 - 1 1/3
W = 2 11/12 quarts

So, 2 11/12 watermelon juice is added.