In a factory, the machines breakdown on an average rate of 8 machines per hour. The idle time cost of a machine is estimated to be 50 AED per hour. The factory works 8 hours a day. The factory management is considering 3 mechanic crews for repairing the machines. The crews are working together on the same machine during repair activities. The first crew A consist of one mechanic and takes about 30 minutes on an average to repair a machine and demands wages of 50AED per hour. The second crew B which consist of three mechanics can service 9 machines per hour and demands wages at the rate of 40 AED per hour per mechanic. The third crew which consist of four mechanics takes about 6 minutes on an average to repair a machine and demands wages of 40AED per hour per mechanic. Assuming that the rate of machine breakdown is Poisson distributed and the repair rate is exponentially distributed. Which one of the crews should be considered?