Diego can carry 20 pounds of fruit home in his bookbag. If he buys a pound of watermelon, a pound of grapes, and a pound of oranges, how many pounds of apples can he buy?
He is able to carry 3 pounds of watermelon, grapes, and oranges because1+1+ 1 = <<3=3>>3
He can buy 17 pounds of apple because20-3 = <<20-3=17>>17
#### 17