Find appliance-shipping arrangement to minimize costs

[jim b.]

This problem is about transportation:

An appliance company has a warehouse and two terminals. To minimize shipping cost, the manager must decide how many appliances should be shipped to each terminal. There is a total supply of 1,200 units in the warehouse and a demand for 400 units and terminal A and 500 units and terminal B. Shipping to terminal A is $12, to terminal B is $16. How many units should be shipped to each terminal in order to minimize cost?

 

[tkhunny]

Don't ship any to either terminal. The cost is $0.

Unfortunately, the problem statement, as presented, really doesn't provide much guidance as to what the goals are. Must all 1200 ship? Can we quit at 900?