After visiting one of my very old relatives, I travelled home in their 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 was it from my relative's house to my home?
Puzzle Copyright © Kevin Stone
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Answer
150 miles.
Reasoning
I was travelling at 30mph at a rate of 20 mpg, so I was using 1.5 gallons every hour for the driving itself.
I was also losing 0.5 gallons 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.
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