Consider the question. Abigail is trying a new recipe for a cold drink. It uses 1/4 of a cup of iced tea and 1 and 1/4 of a cup of lemonade to make one drink. If she fills a pitcher with 18 total cups of this drink, how many cups of lemonade are in the pitcher?
 If the answer is '15'; explain the reasoning:
Each drink uses 1.5 cups because 1 / 4 cup + 1 and 1 / 4 cup = 1.5 cups. The pitcher contains 12 total drinks because 18 / 1.5 = 12. There are 15 cups of lemonade in the pitcher because 12 x 1 and 1 / 4 = 15.