Decimals

Question #13

The school cafeteria is making peanut butter cookies as a holiday treat for the students. In order to make enough for all of the students, they will need peanut butter, 2.5 cups of shortening, 3.25 cups of both white and brown sugar, and 6.5 cups of flour. After mixing the listed ingredients together they have a total of 18.25 cups. How many cups of peanut butter did they use?