Can someone help me with this asap?

A large gasoline engine uses a heat output equal to 10,000 J to perform work equal to 2,000 J per cycle. The engine runs at 25 cycles per second. The heat is obtained by burning petrol. The heat of combustion for petrol is 50 J/g.

a) Calculate the Carnot efficiency of the engine. b) What is the amount of heat given off to the environment per cycle? c) How much work is done per second? d) Calculate the mass of petrol that must be burned in 45 minutes?