A repair men is to be hired to repair machines which break down at an average rate of 3/h. The break down following the Poissonian Law. Non productive time of a machine is considered to cost Rs. 10/h. Two repairman have been contacted. One A, charge Rs. 5 per hour and repairs 4 breakdowns machines/hr. While B charges Rs. 7 per hour and repairs 6 such faults/hr. Find which repair man should be hired. (1 day = 8 hour working).