Question

A driver fills her car up completely with 15 gallons of gas. She will drive at an average of 60 miles per hour until she only has a quarter tank left; at which point she will stop and refuel. If her car averages 28 miles per gallon, how much time will pass before she stops to refuel?

Answer 1

5.25 hours are expected

Explanation:

The driver's car contains 15 gallons of gas.

She will drive until she has a quarter tank left, which means she will use 3 quarters or 75%.

75% of 15 is 11.25, meaning she will use 11.25 gallons.

The car averages 28 miles per gallon, which means it can go

11.25 gallons * 28 miles/gallon = 315 miles

She travels an average of 60 miles per hour

315 miles / 60 miles/hour = 5.25 hours.

As this is the math world, this expects that the car is 100% efficient, there are exactly 15 gallons, and that it goes exactly 28 miles per gallon.