In: Operations Management
Consider a transportation problem, shipping a product from two sources to two customers. The following table shows the data.
Write a LP model for this problem to minimize the shipping cost (unit in $) while satisfying the demand for each customer and supply for each source. You don’t need to solve your LP model. I just need a LP model only.
Customer1 |
Customer2 |
Supply |
|
Source 1 |
$8/unit |
15 |
15 |
Source 2 |
11 |
7 |
20 |
Demand |
12 |
23 |
Variable Definition:
Xij = Shipment volume from source to customer where i = 1,2 and j = 1, 2
For example, X11 represents shipment volume from source 1 to Customer 1
For example, X12 represents shipment volume from source 1 to Customer 2
Objective Function:
Cost while shipping from source 1 to Customer 1 = $8
Hence, Cost while shipping X11 products motors from source 1 to Customer 1 = 8*X11
Similarly, the cost for all shipment routes can be calculated.
Total Cost= 8*X11 + 15*X12 + 11*X21 + 7*X22
We'd like to minimize the cost.
Therefore,
Minimize Z = 8*X11 + 15*X12 + 11*X21 + 7*X22
Constraints:
Total demand = 12 + 23 = 35
Total Supply = 15 + 20 = 35
As this is a balanced transportation problem (Demand = Supply) complete capacity of every source is expected to be used.
X11 + X12 = 15 ..... Supply constraint on source 1
X21 + X22 = 20 ..... Supply constraint on source 2
As this is a balanced transportation problem (Demand = Supply) complete demand of every customer is expected to be satisfied.
X11 + X21 =12 ..... Demand constraint on customer 1
X12 + X22 =23 ..... Demand constraint on customer 2
Non-negativity Restriction
Xij >=0 .........Non-negativity constraint as volume shipped cannot be negative in value