Calculate the overall efficiency, the heat rate [MW], and the total fuel rate [kg/s] of a combined-cycle power plant (1) if no supplemental firing is used and (2) if 30% of the gas turbine fuel demand is additionally burned in the supplementary firing of the HRSG. The gas turbine plant and steam turbine plant thermal efficiencies are 37.5% and 26% [both based on lower heating value (LHV)], respectively. Assume that the combined-cycle power plant has an electrical power output of 380 MW and that the fuel HFO No.2 has the lower heating value of 43 MJ/kg.