1.
As of March 31, the XYZ Soft Drink Company had 86 workers on the payroll. To
plan the production from April through September, the demand for the next six
months is estimated 9500, 9300, 12200, 17600, 14000, 5300 cases. The number of
working days from April to September are 11, 22, 20, 23, 16, 20. Over a period of 26
working days when there were 100 workers on the payroll, the company produced
12000 cases of soft drink. Assume that the cost of holding one case of soft drink per
month is 75 cents. The cost of hiring per worker is $125 and the cost of firing per
worker is $300. The company currently has 4500 cases of soft drink in inventory and
would like to start October with 3000 cases on hand. Evaluate the cost of constant
workforce plan.
2. XYZ computer store is open 300 days per year. Average daily demand for LCD
monitor is normally distributed with a mean of 20 units and a standard deviation of
3 units. The cost of ordering LCD is $15, and carrying cost is $18 per LCD per year.
Lead time is fixed at 5 days.
a. What is the EOQ?
b. What reorder point provides for a service level of 95 percent?
c. What is the expected number of units short per cycle with 95 percent service level?
d. What is the expected number of units short per year with 95 percent service level?
e. What is the annual service level?
f. Suppose the management has changed the ordering policy for this item from EOQ
to FOI (Fixed Order Interval) and set the order interval (OI) to 25 days. Compute
the order quantity for this LCD monitor if there are 45 LCDs on hand at the time
order is placed.
3.
A computer store is open 300 days per year. Average daily demand for LCD
monitor is normally distributed with a mean of 20 units and a standard deviation of 3
units. The cost of ordering LCD is $15, and carrying cost is $18 per LCD per year.
Lead time is fixed at 5 days.
a.
b.
c.
d.
e.
f.
What is the EOQ?
What reorder point provides for a service level of 95 percent?
What is the expected number of units short per cycle with 95 percent service level?
What is the expected number of units short per year with 95 percent service level?
What is the annual service level?
Suppose the management has changed the ordering policy for this item from EOQ
to FOI (Fixed Order Interval) and set the order interval (OI) to 25 days. Compute
the order quantity for this LCD monitor if there are 45 LCDs on hand at the time
order is placed.
4. The operations manager of a body and paint shop has five cars to schedule for repair. He
would like to minimize the throughput time (makespan) to complete all work on these cars.
Each car requires body work prior to painting. The estimates of the times required to do the
body and paint work on each are as follows:
Car
A
B
C
D
E
Body Work
(Hours)
8
9
7
3
12
Paint (Hours)
7
4
9
4
5
a. Use a Gantt Chart to show the progress of these five jobs through the two centers on the
basis of the arbitrary order
A BCDE
What will be the makespan (after how many hours will all jobs be completed) and idle
time for paint shop? (25 pt)
b. Use Johnson's rule to determine the optimal sequence of these five jobs. (30 pt)
c. Use a Gantt Chart to show the progress of the five jobs in this optimal sequence and
calculate the makespan and the idle time for paint shop. (45 pt)