Problem No. 2:

Tri-County Utilities, Inc. supplies natural gas to customers in three-country area. The company purchases natural gas from two companies: Southern Gas and Northwest Gas. Demand forecasts for the coming winter season are Hamilton County, 400 units; Butler County, 200 units; and Clermont County, 300 units. Contracts to provide the following quantities have been written: Southern Gas, 500 units; and Northwest Gas, 400 units. Distribution costs for the counties vary, depending upon the location of the suppliers. The distribution costs per unit (in thousands of dollars) are as follows:

		To
From	Hamilton	Butler	Clermont
Southern Gas	10	20	15
Northwest Gas	12	15	18

Solve the problem and find the optimal solution.