Jamie and stella are saving money to sign up for a school trip to washington, d. c. in order to sign up for the trip, they must pay $600 upfront. jamie earns his money by washing cars for $25 each. stella earns her money by making pecan pies for $15 each. jamie earns more money than stella does because stella only has enough supplies to make 40 pies. let x represent the number of cars jamie washes. let y represent the number of pies stella makes.