For each problem, make an Excel model, simulate via YASAI, and hand in the
standard printouts for a
simulation problem.
Q1. (50 points) Your company can deliver its products using either leased trucks or a courier service. You do not know in advance the exact number of orders you will need to deliver, but in the past it has followed the following pattern:
| Number of Orders to Deliver | Percent of the Time |
| 15 | 5% |
| 16 | 7% |
| 17 | 9% |
| 18 | 10% |
| 19 | 13% |
| 20 | 14% |
| 21 | 13% |
| 22 | 11% |
| 23 | 8% |
| 24 | 6% |
| 25 | 4% |
Each leased truck has a 94% chance, independent of all other trucks, of being
serviceable on any given day, in which case it can deliver up to 5 orders at a
cost of $20 per order. If a truck is not serviceable, it cannot deliver any
orders. Each truck also costs $80 per day to lease, but only on the days it is
serviceable. Orders not delivered by leased truck are delivered by courier at a
cost of $95 each. How many trucks should you lease in order to minimize your
average total daily leasing and delivery cost? Simulate 3, 4, 5, and 6
trucks, each for 1000 days. With the optimal number of trucks, what is the
average number of orders per day that have to be shipped by courier?
Q2. (50 points) You manage a biotechnology plant that uses genetically-engineered microbes to produce pharmaceuticals. The microbes grow in large vessels called "incubators". You have 20 Type A incubators and 10 Type B incubators. On any given day, each Type A incubator has a 19% chance of needing to be serviced, independent of all other incubators. Each Type B incubator has a similar 8% chance of needing service. Servicing a Type A unit takes 2.1 hours of labor, and servicing a Type B unit takes 3.8 hours of labor.
Servicing can be done by in-house service people or by an outside contractor. Each in-house service person costs $550 per day. Each service person has a 92% chance of being able to work on any given day, independent of all other service people (the remaining 8% of the time comprises sick days, vacation, training, and paperwork; however, service people are always paid whether they are available to work or not). Each available service person can provide up to 7 hours of labor per day.
If you do not have enough in-house labor hours to service all the incubators that need attention on a given day, you must supplement your in-house service people with outside contractor labor, at a cost of $250 per hour.
By simulating 1000 days of operation with YASAI, estimate whether it is best to hire 0, 1, 2, 3, 4, 5, or 6 in-house service people.