A plant has a large number of similar machines breakdown/failure are random and independent. The shift in charge of a plant collected the data about various times, machine break down & repair time required on hourly basis & the data are tabulated.
First table is the time 4 machine break down & then probability
0.5 0.05
1 0.06
1.5 0.16
2.0 0.33
2.5 0.21
3 0.19
Second table is
Repair time required Probability
1 0.28
2 0.52
3 0.20
For each hour that a machine is down due to being repaired or waiting to be repaired, the plant loses 70 rupee a by way of cost production. A repair man is paid 20rupees per hour. Simulate this maintenance system for 15 breakdown & how many repair men should the plant hire for repair work?