In a heat engine, 3.00 mol of a monatomic ideal gas, initially at 4.00 atm of pressure, undergoes an isothermal expansion, increasing its volume by a factor of 9.50 at a constant temperature of 650.0 K. The gas is then compressed at a constant pressure to its original volume. Finally, the pressure is increased at constant volume back to the original pressure.

(a) Calculate the work done by the engine during each step and the net work done per cycle. 

(b) If the heat input per cycle is 58.3 kJ, what is the efficiency?