A two - stage compressor with a clearance of 6% receives 80 lb/min of air at 14 psia and 850F and delivers it at 120 psia. The compressions are polytropic with n=1.30, and the intercooler cools the air back to 850F. 

Find 

(a) the work, 

(b) the heat transferred in the various processes, 

(c) the work for a single - stage machine, 

(d) the corresponding percentage saving for the two - stage machine, and 

(f) the mass of water to be circulated through the intercooler if its temperature rise is 15% 0F