1. Every time a machine breaks down at the ATD Manufacturing Company, either one, two, or three hours are required to fix it, according to the following probability distribution.

Machine Breakdowns Per Week	Probability
0	0.15
1	0.15
2	0.25
3	0.30
4	0.10
5	0.05
	1.00

Repair Time (hr.)	Probability
1	0.35
2	0.40
3	0.25
	1.00

1. Simulate the repair time for 20 weeks, and then compute the average weekly repair time.
2. If the random numbers that are used to simulate breakdowns per week are also used to simulate repair time per breakdown, will the results be affected in any way? Explain.
3. If it costs $200 per hour to repair a machine when it breaks down (including lost productivity), determine the average weekly breakdown cost.
4. ATD is considering a preventive maintenance program that would alter the probabilities of machine breakdowns per week as shown in the following table. The weekly cost of the preventive maintenance program is $300. Using simulation, determine whether or not the company should institute the preventive maintenance program.

Machine Breakdowns Per Week	Probability
0	0.40
1	0.20
2	0.15
3	0.10
4	0.10
5	0.05
	1.00

Repair Time (hr.)	Probability
1	0.50
2	0.35
3	0.15
	1.00