Practice Problems on Process Analysis Essay

762 Words Dec 5th, 2014 4 Pages
Operations Management 70371
Practice Problems on Process Analysis: Solutions
1. On a typical weekday in January, 4,200 customers visit the Pittsburgh Wal-Mart. It is estimated that, on average, there are 350 customers in the store. Assuming that the store is open 14 hours a day, how much time does the average customer spend in the store? Solution:
- Since the average number of customers in the store is 350, I=350.
- 4,200 customers go through the system in a 14 hr. day. Thus, the throughput rate
(R) is 4200 customers/day or 4200/14 = 300 customers/hr.
- Applying Little’s Law (I=R*T) the time an average customer spends in the store is: T=I/R = 350/300 = 1.17 hours = 70 minutes
2. In 2006, Shouldice Hospital admitted 14,965 patients. In
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The number of men is: I(m) = R(m)*T(m) = 150 * T(m).
Consequently, the number of women is the double of the number of men, and therefore, 2/3 of the employees are women.

4. The Internal Revenue Service Department of Tax Regulations writes regulations in accord with laws passed by Congress. On average, the department completes 300 projects per year. The Wall Street Journal reports that, as of October 11, 1997, the number of projects currently "on the Department’s plate" is 588. Nevertheless, the department head claims that average time to complete a project is under six months.
Do you have any reason to disagree? Why or why not?
- Inventory I = 588 projects
- Throughput R = 300 projects/yr (we assume a stable system).
- Thus, average flow time T = I / R = 588 / 300 = 1.96 yr.
- This is much larger than six months. So we should disagree with the department head’s statement.
5. A bank finds that the average number of people waiting in line during lunch hour is
10. On average, during this period 2 people per minute leave the bank after receiving service. On average, how long do bank customers wait in line?
- Average inventory I = 10 people
- Throughput R = 2 people/min (we assume a stable system).
- Thus, average flow time T = I / R = 10 / 2 min = 5 min.
6. At the drive-through counter of a fast-food outlet, an average of 10 cars waits in line.
The manager wants to determine if the length of the line impacts potential

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