Operation Management – Waiting Lines Homework Assignment – Some assistance
BOOK: Jay Heizer and Barry Render. Operations Management, Flexible Edition. 10thEdition.
Here is a link for the book:
https://drive.google.com/file/d/1LeBBcIUs5UkOS3fvx2nXdo06dN8FfwXt/view?usp=sharing
Instructions:
Work the Practice Problems for Waiting Lines homework assignment – some assistance:
- Please read and review the Waiting Lines homework assignment – some assistance carefully, before you start solving these problems. Then, upload your answers in a Word document.
- You must show all your calculations work, or credit will not be given!
- Work the problems in this document. They make you use one or more of the models you have studied.
- Figure out first which model is relevant; then use the formulas and charts to obtain the answers for the performance measures asked about.
Problems 68-71 use 5 machines. See Table D.8 in the book on page 601.
Some tips for Qs #7 & #8:
Let’s start with #7. This is an M/M/1 (page 591)
The first thing that you need to figure out is how many vehicles are “out of service,” which is the number of vehicles in the system, which is Ls.
The problem statement says that it costs $150 per vehicle per day to be out of service. So, the “cost” of the number of vehicles out of service is Ls x $150
There is also labor cost per day. The total cost per day is therefore the labor cost plus the cost of the vehicles that are out of service.
Now for #8. This is an M/M/S (page 594)- more specifically, an M/M/2 (two crews)
You do the cost in the same way as in #7, but with different formulas. Figure out Ls, then multiply that by the cost of the breakdown ($150) – this is the machine cost of the system. Then you add labor cost like you did in #7, then that is the total cost.
The challenge on this one is to calculate Ls. Look at the formula on page 594. To calculate Ls, you first need to do Po. M=2, arrival rate = 8, service rate = 11.
Calculate Po, then Ls, then do the machine and labor costs!
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