4 cups=1 quart 4 quarts=1 gallon The math: 5.5 gallons* (4 quarts/1 gallon) = 22 quarts 22 quarts * (4 cups/1 quart) = 88 cups So in 5.5 gallons there are 22 quarts, and in 22 quarts there are 88 cups. Therefore in 5.5 gallons, there is 88 cups.

If you use 12 ounce cups, you need 1360 ounces of drink. That is one drink per person. There are 64 ounces in a gallon, therefore you need at least 22 gallons of drink.