After visiting her Uncle Abner, Belinda traveled home in his old car. The car had a leak from the petrol tank, and she was stuck in second gear.

This meant that Belinda 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 Belinda had placed exactly 10 gallons of fuel into the tank. She knew though, that the fuel tank lost fuel at the rate of half a gallon per hour.

Just as Belinda arrived home, the car stopped because it had run out of fuel and Belinda had only just made it.

How far was it from Uncle Abner’s to Belinda’s home?