Advanced Modeling Problem in Excel

Consider a transportation problem in which goods have to be transported from 3 sources labeled as S1, S2 and S3 to 4 destinations labeled as D1, D2, D3 and D4. The costs in euros per unit transported from a source to a destination are given in the following table. It also contains the demand at the destinations and the available supply at the sources:

Source\\ Destination D1 D2 D3 DA Supply at source: S1 10 0 20 11 20 S2 12 7 CO 20 25 S3 0 14 16 18 15 Demand at destination: 10 15 15 20