Operations Management (33:623:386) 
Spring 2005, Professor Eckstein et al.
Assignment 4

Due: Friday, February 18

For each problem below, hand in an algebra formulation, and also solve using Excel and Solver, handing in the standard printouts.
 

Q1. (25 points)  Problem 10 on page 50 of the course pack (BullCo Fertilizer).

 

Q2. (30 points)  Problem 60 on page 77 of the course pack (Candy Kane cosmetics).  

 

Q3. (45 points)  Your firm makes fluorescent paint pigments in four plants and ship them to four distributors (abbreviated "D1" through "D4"), as follows:

Unit Shipping Cost To

Plant

Capacity

Unit Cost

Impurities

D1 D2 D3 D4
Northeast 1000  $   12.40 12  $ 1.20  $  1.75  $  2.35  $  2.85
Southeast 1250  $   11.55 15  $ 1.95  $  1.35  $  1.75  $  2.15
Northwest 950  $   10.85 18  $  2.45  $  1.50  $   2.10  $  1.95
Southwest 1200  $   12.05 12  $  2.75  $  2.25  $   2.00  $  1.45

The distributors' demand for the pigments is as follows:

D1 D2 D3 D4
Max Impurities 15.0 15.0 14.0 15.5
Base Demand 700 600 550 675
Advertising Sensitivity 0.05 0.1 0.05 0.125

For example, distributor D1 will accept up to 700 units of pigment, plus 0.05 units for every dollar you spend on national advertising.  Advertising is not separated by distributor: a single expenditure affects all distributors simultaneously.  Thus, if you spend $100 on advertising, D1's demand will be 700 + (0.05)(100) = 705 units, D2's demand will be 600 + (0.1)(100) = 610 units, D3's demand will be 555 units, and D4's demand will be 687.5 units.

"Max impurities" indicates the maximum average impurity level allowed for shipments to each distributor.  For instance, the shipments from the four plants to D1, when mixed together, should have an average impurity level of at most 15.0.

You have at most $59,000 to spend on production, shipping and advertising, and all the distributors pay you $28.50 per unit.  How can you maximize your profits?

Note: this problem combines blending, transportation, and elements of the "pickles" problem.  Do not be worried if  your solution contains a lot of fractions.  To save typing, you may download the data for this problem here.