University of Business and Technology
College of Engineering
Industrial Engineering Department
Spring 2018
IE 311 Operations Research
Contest Problems
The following problems are for extra marks. They are typical to what you would
utilize LP for in real life. This is a classic Aggregate Production Planning
problem that aim to reduce the production planning cost. [You will cover this
topic in more details in the Production Planning and Control Course].
1. A company would like to plan its production for next year. Its goal is to minimize the
total manufacturing cost. The following table present the monthly demand, unit
production cost, and production capacity.
Month Demand Production
Capacity
Production
Cost $ per unit
January XXXXXXXXXX
Fe
uary XXXXXXXXXX
March XXXXXXXXXX
April XXXXXXXXXX
May XXXXXXXXXX
June XXXXXXXXXX
July XXXXXXXXXX
August XXXXXXXXXX
September XXXXXXXXXX
October XXXXXXXXXX
November XXXXXXXXXX
December XXXXXXXXXX
If the inventory data is as follows:
ï‚· Maximum Inventory level per month is 350 units.
ï‚· Inventory holding cost per month is $1.5 per unit.
ï‚· At the start of January there were 90 unit in inventory
Formulate the problem as a LP problem then use the excel solver or any other software to
determine how many units the company should:
ï‚· produce each month
ï‚· and how many units should be in the inventory each month
in order to minimize the total manufacturing cost and satisfy the monthly demand.
3 Marks
2. If the company in addition to the aforementioned information can also use overtime to
increase its production capabilities. The following table shows the overtime cost per unit
produced in overtime and the maximum amount of units that can be produced by
overtime for each month.
Month Over time cost
$ per unit produced in
over time
max number of units
produced by overtime
January XXXXXXXXXX
Fe
uary XXXXXXXXXX
March 25 200
April XXXXXXXXXX
May XXXXXXXXXX
June XXXXXXXXXX
July 25 150
August XXXXXXXXXX
September XXXXXXXXXX
October 25 200
November XXXXXXXXXX
December XXXXXXXXXX
Formulate the production plan as a LP problem then use the excel solver or any other software to
determine how many
ï‚· units should be produced by regular production each month
ï‚· units should be produced by over time each month
ï‚· units should be stored in the inventory each month
in order to reduce the total manufacturing cost and satisfy the monthly demand
2 Marks