Question

John has a job parking cars. He earns a fixed weekly salary of $180 plus a fee of $3 for each car he parks. His potential earnings for a week are shown in the graph. At what point does John begin to earn more from fees than his fixed salary? Complete the justification of your answer. Earnings 800 Weekly Earnings 395 300 225 150 S Cars parked 10 40 50 50 70 SO 90 100 John earns the same in fees as his fixed salary when he parks si - S fee per car = cars. He starts earning more from fees than his salary when he parks cars.

Answer 1

In order to determine at what point does John begin to earn more from fees than his fixed salary, consider that the weekly fixed salary is $180. Then it is necessary that John earns more than $180 from fees.

In the graph the searched point is the point with a salary of mores than

2x180 = 360 becasue for this salary John earns more from fees that from his fixed salary.

You can notice that from 60 cars parked the John's salary is at least $360.

Then, for the point (60,360) John earns more from fees than his fixed salary.