Two hundred gallons of fuel oil are purchased at $0.91 per gallon and are consumed at a rate of $0.70 worth of fuel per hour. At this rate, how many hours are required to consume the 200 gallons of fuel oil?
1 gallon costs $0.91;
Consumed at a rate of $0.70 worth of fuel per hour.
So, in 1 hour 0.7/0.91 gallons are consumed. Therefore, 200 gallons will be consumed in 200/(0.7/0.91) = 260 hours.