$[4]$ An oil fired boiler working at a pressure of $1000$kPa generates $3,500k\frac{g}{h}r$ of steam. The feed water temperature is $90C$ and the steam leaves the boiler at $400C.$ If the heating value of the oil is $42M\frac{J}{k}g$ and fuel consumption is $7200k\frac{g}{?}$ day, determine:

a$)$ The factor of evaporation

b$)$ The boiler efficiency

c$)$ The equivalent evaporation