Mark, the director of a summer camp, must purchase prizes for the annual talent show. He spent a total of $198 on prizes for the top 14 performers.
Each performer receives either a $15 gift certificate for pizza or a gift
certificate for a stuffed animal worth $13, but he can't remember how
many of each prize he bought. Below are equations that three students
wrote to find the number of gift certificates x.
Which equation(s) could you use to solve this problem?
Laura: 15x + 13x = 198
Ellie: 15x + 13(14 - x) = 198
Robert: (15 + 13)x=198