which would get better gas mileage

imported post

Both vehicles are identical in every way, they will be travelling at the same speed on the same road. The only difference will be that it is a hot day to be in the four doortruck, so one vehicle has all the windows open and the A/C is off. The second truck has all the windows up but the A/C is on. They both have 5 gallons of gasoline in their tanks. Who will run out of gas first.