(Adapted from Winston and Albright)

Supplying Power at Midwest Electric: Midwest Electric has three electric power plants that supply the power needs of four cities. Each power plant can supply the amounts shown in the table below (in millions of kilowatt-hours of electricity):

	Supply
Plant 1	35
Plant 2	50
Plant 3	40

The peak power demand (again in millions of kwh) at each city is given in the following table:

	Demand
City 1	45
City 2	20
City 3	30
City 4	30

Finally, the cost (in dollars) of sending a million kwh from each plant to each city is given in the following table:

	City 1	City 2	City 3	City 4
Plant 1	8	6	10	9
Plant 2	9	12	13	7
Plant 3	12	9	16	5

Midwest Electric wants to find the lowest-cost method for meeting the demand of the four cities.

1. Build a network flow model for Midwest and solve it using solver. (1 points)
2. Identify the binding and the nonbinding constraints in your solution. (0.5 point)
3. Pick a constraint of your choice in your model. What is the shadow price for this constraint? What does this shadow price mean in words? (1 point)