After visiting my Great Aunt Annie, I travelled home in her old jalopy. The car
was old and battered, it had a leak from the petrol tank, and I was
stuck in second gear.
This meant that I could
only travel along at a
steady 30 miles per hour and managed a
paltry 20 miles per gallon of fuel. At the
start of the journey I had placed exactly
10 gallons of fuel
into the tank. I knew though, that the fuel
tank lost fuel at the rate of half a gallon
per hour. Just as I arrived home, the car
stopped because it had run out of fuel
and I had only just made it. How far it was from my Great Aunt's to my home?
30 miles..... .......
I was travelling at 30mph at a rate of 20mpg, so I was using 1.5 gallons every hour for the driving itself.
I was also losing 0.5 gallon every hour. In total, I was using 2 gallons every hour.
Therefore to use all of the 10 gallons I started with, I travelled for 5 hours.
5 hours at 30mph is 150 miles.
Hope this helps