If you have time, please read & help :D

[Leixer]

These are math problems while using Spread sheet, for some this might be hard, some could be fair or easy, for me it's hard hehe. can any 1 help me on solving this?i have small knowledge in excel spreadsheet THANK YOU, not sure if this is the right place for this topic

 

PROBLEMS:

 

1. A company that makes concrete sells it in three quality levels, type 1 the being lowest, and type

3 being the highest. After deducting all variable costs, the net revenue is $30 per Tonne for

type 1, $40 for type 2, and $50 per type 3. There are three operations, each of which limits the

amount of production: crushing, grinding, and mixing. In addition, each type of concrete must

be inspected. The model has been formulated as:

Let X1, X2, and X3 represent respectively the number of type 1, 2, and 3 made in Tonnes per

hour.

maximize 30X1 + 40X2 + 50X3

subject to

Crushing 2X1 + 4X2 + 5X3 80

Grinding 6X1 + 8X2 + 12X3 210

Mixing 5X1 + 7X2 + 8X3 146

Inspection 3X1 + 4X2 + 5X3 50

non-negativity X1 ; X2 ; X3 0

(a) Solve using a spreadsheet Solver, and print the Answer and Sensitivity Reports.

(b) State the solution in words, and indicate which constraints are binding.

(c) By using the information from the Sensitivity Report (NOT by re-running the model each

time), give the predicted change to the objective function value (and the reasoning behind your

answer) for the following situations (taken one at a time). If the OFV cannot be predicted

exactly, then give an answer such as “the OFV will increase by at least $100”.

(i) The revenue per Tonne for type 1 concrete rises by $0.70.

(ii) There are three fewer units of crushing.

(iii) The revenue per Tonne for type 2 concrete increases by $8.00.

(iv) The number of units of grinding decreases by 20.

(v) The number of units of mixing increases by nine.

(vi) The price per Tonnes of Type 1 cement falls by $3, and the price for Type 3 concrete rises

by $15.

(See the next page for the second problem.)

1

2. A company makes calculators at facilities in Shanghai (China), Bonn (Germany), and Cape

Town (South Africa). These plants can make 1800, 900, and 2700 calculators per week beyond

the demand in the “local” markets of Eastern Asia, Germany, and Africa respectively. All three

plants can ship to markets elsewhere: Canada/USA, Latin America, Europe, and Western Asia.

The demands per week in these three markets are for 1500, 600, 750, and 2300 calculators per

week respectively. Calculators are shipped in boxes of 50. The shipping costs per box are as

follows:

From/To Canada/USA Latin America Europe Western Asia

Shanghai 180 270 205 120

Bonn 230 250 80 190

Cape Town 200 210 185 220

(a) Formulate a model in Excel (there is no need to give the algebraic model) and solve it to

determine how much should be shipped from the factories to the markets. State the solution

in words.

(b) Now suppose that calculators can be shipped from Cape Town to Bonn at a cost of $15 per

box. For legal reasons, Shanghai cannot transship to Bonn. Formulate a model in Excel

and solve it, and state the solution in words.

 

[Aquellia]

I made a quick search for linear programming in excel:

http://www.youtube.com/watch?v=RicajFzoenk

 

I hope that helps, If not searching for 'linear programming in excel'  or 'linear programming using excel solver' should give you plenty of other results.

[Leixer]

thank you :D