A hunting lodge has enough fuel to keep 20 room heated for fourteen days A hunting lodge has enough fuel to keep 20 room heated for fourteen days . If the lodge decides to save fuel by turning off the heat in 5 unoccupied rooms, and each room requires the same amount of fuel to heat it, how many extra full days will the fuel supply last ?

The fuel is enough for 20*14 = 280 room-days. If you're heating 15 rooms, you can sustain heat for 280/15 = 18.6666... days. That's four extra FULL days.