13. Kaya rented a boat from a marina for a fee of $50, plus $3 for every gallon of gas she used. When she returned the boat, Kaya was given a bill of $98. She had kept track of her gas usage and thought that the bill was in error—specifically, that the bill was $21 more than it should have been. If Kaya was correct, how many gallons of gas did Kaya use during her rental?

Answer and Explanation

Your Answer is

Correct Answer is C

Explanation

First calculate the real cost of Kaya, which is 98-21=77; then if you use x gallons of oil, you can get 77=50+3x