We are trying to figure out how many copy machines we should install in the basement of Stranahan Hall. Copy machines should be available 24/7. Students may walk up at any time of the day or night for copying. Based on past data, it can be assumed that the amount of time a student needs to use the copy machine is described by a discrete probability distribution listed below:
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Copying time (in min)
|
Probability
|
|
1
|
0.25
|
|
2
|
0.25
|
|
3
|
0.25
|
|
4
|
0.25
|
Interarrival times for student arrivals at the copy machine(s) is described by the following discrete distribution-
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Interarrival time (min)
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Probability
|
|
1
|
0.2
|
|
2
|
0.2
|
|
3
|
0.2
|
|
4
|
0.15
|
|
5
|
0.25
|
Students hate spending time waiting at the copy machines for their turn to use them. Students don't depart from the queue until they use the machine. Service policy is - first come, first serve (whoever arrives first at the machine gets the priority to use the machine). Suppose that students time is valued at $10 per hour, i.e., the student could have used the any time wasted just waiting could have been put to use at that wage rate. Each copy machine can be leased at rate of $10 per day. Cost of leasing copy machines is ultimately charged to the common student services. Given the above information, answer the following-
- Assume that the university leases one copy machine. What is the total cost of operating the system per day? (this cost includes the cost of time wasted by the students waiting at the copy machine plus the cost of leasing the copy machine).
- Assume that the university leases two copy machines. What is the total cost of operating the system per day?
- Assume that the university leases three copy machines. What is the total cost of operating the system per day?
You must use Simul 8 to build the model, and obtain necessary information to solve the problem.