An airplane uses a multi-cylinder gasoline engine operating at 2,800 rev/min. It takes in energy of 7.08 103 J and exhausts 1.72 103 J for each revolution of the crankshaft. (a) How many litres of fuel does it consume in 2.0 hours of operation if the heat of combustion of the fuel is 4.43 107 J/L? [ Give your answer in L to the nearest 0.1 L ]