Mrs. Bowser spends $39 on 3 slices of pizza and 5 bags of popcorn. Mrs. Lassetter spends $36.50 on 5 slices of pizza and 2 bags of popcorn. After a couple of hours, they persuade Mr. Tiller to skip his next class to join them. Mr. Tiller comes over and he buys 6 slices of pizza and 5 bags of popcorn. How much money does Mr. Tiller spend?