Your answer is 72 ounces
Problem: How many gallons were in the bowls at the start?
less the 34 cups they served during the first intermissionplus the amount the sixth-graders added, made after the first intermission (during the second act)less the quantity served during the second intermission
The result is the 2 gallons of punch at the end of the performance.
To find out how many gallons they had to begin with, work backward, starting with the 2 gallons left at the end of the performance. When working backward, reverse the operations that occurred in the story from beginning to end. Do this by following the steps below.