Mary spent a total of $291.94 for a party. She spent $200.29 on food, plus an additional $30.55 for

[math_celebrity]

Mary spent a total of $291.94 for a party. She spent $200.29 on food, plus an additional $30.55 for each hour of the party. How long was the party?

First, figure out the remaining cost after food:
291.94 -200.29 = 91.65

91.65 / 30.55 per hour = 3 hours