Question

A car traveled 243 miles on a trip. During 63 miles of the trip, the car traveled through the city and had gas mileage that was 9 fewer miles per gallon that the gas mileage on the highway. If the total amount of gasoline used for the trip was 9 gallons, find the gas mileage of the car on the highway. Please help ASAP!!! :(

Answer 1

gas used is miles / mpg, so add up the gas for each leg of the trip:
63/(x-9) + 180/x = 9
Now just solve for x. Discard the meaningless answer.