At a steam power plant, steam engines work in pairs the output of heat from one being the approximate heat input of the second. The operating temperatures of the first are 670oC and 440oC, and of the second 430oC and 290oC if the heat of combustion of coal is 2.8 X 107 J/kg, at what rate must coal be burned if the plant if to put out 1100 MW of power? Assume the efficiency of the engines is 60% of the ideal (Carnot) efficiency.