Lance is a local scrap merchant. He had to travel to the county recycling plant, 60 miles away. On the way there he could only manage a steady 12 miles per hour (mph), fully laden.
On the way back,Lance could manage a steady 16mph. He placed 24 gallons of fuel in the tank ready for the round trip, thinking that this would be enough as the wagon managed to travel 8 miles per gallon.
Unfortunately, a piece of metal pierced his fuel pipe at the start of the trip and the wagon started to lose 1 gallon of fuel per hour.
Luckily he only lost fuel when moving and he lost no fuel whilst unloading his scrap metal.
Were 24 gallons enough for the round trip?
At 8 mpg, 24 gallons would last 192 miles.
The fuel actually used (rather than lost) was 120 mi / (8 mi/gal) = 15 gal.
The trip took 60 mi / (12 mi/hr) + 60 mi / (16 mi/hr) = 8.75 hr and he lost 8.75 gal.
That adds up to 23.75 gallons used+lost. He has 0.25 gallons left after successfully completing the trip.
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Posted by Charlie
on 2023-08-06 09:59:48 |
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