A fire tube steam generator with a rated boiler horsepower of 150, consumed 436 kg/min of coal with HHV=7000 kcal/kg. The feed temperature is 80°C and steam is generated at 20.5 kg/cm2 ab. with a temperature of 300°C. The developed boiler horsepower is 225. Determine the 

a). rate of steam generated 

b). heating surface 

c). factor of evaporation 

d). equivalent evaporation