A contractor pays his subcontractors a fixed fee plus mileage for work performed. On a given day the cuntractor is laced with four electrical jobs associated with various projects. He has four electrical subcontractors which are located at various places throughout the area. 

Given below are the distances between the subcontractors and the projects: Required: 

 

How should the contractors be assigned to minimize total costs?

Subcontractor Westside Federated Goliath Universal A 10 14 11 13 B 15 13 9 13 Project C 16 16 8 11 D 18 10 18 9