The highest theoretical efficiency of a gasoline engine, based on the Carnot cycle, is 0.300 or 30.0%.?

Just guessing, if efficiency is work out divided by work in and you have 30 percent efficiency , so 2.95 x 10 to the power of 2 / .30 would give the work in by temperature. work is measured in joules, so i think your answer is 850 j but I could be very wrong.