A vehicle has travelled 90 miles at 40mph

It started its journey with 8 gallons of fuel but its tank has been leaking throughout the journey and is now dry

The vehicle completes the journey at 24mpg

How many gallons of fuel does it leak per hour?

First let us calculate for the total time of the travel using the formula:

time = distance / velocity

time = 90 miles / 40 mph

time = 2.25 hours

Next, we calculate for the total gallons of fuel that is theoretically required:

theoretical amount needed = 90 miles / 24 mpg

theoretical amount needed = 3.75 gallons

The difference of the actual and theoretical amount is the amount which leaked:

amount leaked = 8 gallons - 3.75 gallons

amount leaked = 4.25 gallons

Therefore the amount of gallons leaked per hour is:

amount leaked per hour = 4.25 gallons / 2.25 hours

amount leaked per hour = 1.89 gallons / hr