After visiting my Great Aunt Anne, 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 was it from my Great Aunt's to my home?