Five moles of an ideal gas has pressure P_o, volume V_o and temperature T_o. The gas is expanded to volume 3V_o along a path so that the pressure P is changed as function of volume V as P = P_o (V/V_o). The pressure is then reduced to P_o maintaining the volume constant. The gas undergoes an isobaric compression till the volume & temperature become V_o & T_o respectively. The total work done by the gas during the entire process is