ISCOM/471 – Problem Set 1.

2.4. An electronics company makes communications devices for military contracts. The company just completed two contracts. The navy contract was for 2,300 devices and took 25 workers two weeks (40 hours per week) to complete. The army contract was for 5,500 devices that were produced by 35 workers in three weeks. On which contract were the workers more productive?

2.5. A retail store had sales of $45,000 in April and $56,000 in May. The store employs eight full-time workers who work a 40-hour week. In April the store also had seven part-time workers at 10 hours per week, and in May the store had nine part-timers at 15 hours per week (assume four weeks in each month). Using sales dollars as the measure of output, what is the percentage change in productivity from April to May?

2.6. A parcel delivery company delivered 103,000 packages in 2004, when its average employment was 84 drivers. In 2005 the firm handled 112,000 deliveries with 96 drivers. What was the percentage change in productivity from 2004 to 2005?

5.1. An enterprising student has set up an internship clearinghouse for business students. Each student that uses the service fills out a form and lists up to 10 companies that he or she would like to have contacted. The clearinghouse has a choice of two methods to use for processing the forms. The traditional method requires about 20 minutes to review the form and arrange the information in the proper order for processing. Once this setup is done, it takes only two minutes per company requested to complete the processing. The other alternative uses an optical scan/retrieve system, which takes only a minute to prepare but requires five minutes per company for completing the processing. If it costs about the same amount per minute for processing with either of the two methods, when should each be used?

5.5. A processor makes two components, A and B, which are then packaged together as the final product (each product sold contains one A and one B). The processor can do only one component at a time: either it can make As or it can make Bs. There is a setup time when switching from A to B.

Current plans are to make 100 units of component A, then 100 units of component B, then 100 units of component A, then 100 units of component B, and so forth, where the setup and run times for each component are given below.

COMPONENT / SETUP/CHANGEOVER TIME / RUN TIME/UNIT
A / 5 minutes / 0.2 minute
B / 10 minutes / 0.1 minute

Assume the packaging of the two components is totally automated and takes only two seconds per unit of the final product. This packaging time is small enough that you can ignore it. What is the average hourly output, in terms of the number of units of packaged product (which includes one component A and one component B)?

5.6. The following represents a process used to assemble a chair with an upholstered seat. Stations A, B, and C make the seat; stations J, K, and L assemble the chair frame; station X is where the two subassemblies are brought together; and some final tasks are completed in stations Y and Z. One worker is assigned to each of the stations. Generally there is no inventory kept anywhere in the system, although there is room for one unit between each of the stations that might be used for a brief amount of time.

Given the following amount of work in seconds required at each station:

A / 38 / J / 32 / X / 22
B / 34 / K / 30 / Y / 18
C / 35 / L / 34 / Z / 20

5.6a. What is the possible daily output of this “process” if 8 hours of processing time is available each day?

5.6b. Given your output rate in part a, what is the efficiency of the process?

5.6c. What is the throughput time of the process?

T5.7. In an attempt to increase productivity and reduce costs, Rho Sigma Corporation is planning to install an incentive pay plan in its manufacturing plant. In developing standards for one operation, time-study analysts observed a worker for 30 minutes. During that time the worker completed 42 parts. The analysts rated the worker as producing at 130 percent. The base wage rate of the worker is $5 per hour. The firm has established 15 percent as a fatigue and personal time allowance.

T5.7b. What is the normal time for the task?

T5.7c. If the worker produced 500 units during an eight-hour day, what wages would the worker have earned?