Answer:
The network model is attached.
Step-by-step explanation:
Total Demand from each Gas Company are:
Southern Gas, 500 units;
Northwest Gas, 400 units.
Total Supplies to each County are:
Hamilton County, 400 units;
Butler County, 200 units;
Clermont County, 300 units.
The distribution costs per unit (in thousands of dollars) are as follows
-----------Hamilton-- Butler-- Clermont
Southern Gas--- 10 ---20--- 15
Northwest Gas ----12 ----15---- 18
The network representation of these information is given in the attachment.