A given merchandise must be transported at minimum total cost between three origins (O1, O2, O3) and two destinations (D1, D2). Destination 1 and 2 have placed the following orders: 500 units of the merchandise are demanded by destination 1; 700 units are demanded by destination 2. At the origins, the available amounts of merchandise are 400, 600 and 200, respectively. The unit costs of transportation for the various routes connecting origins to destinations are

a) Set up the primal specification of the transportation problem.

b) Write down the corresponding dual and give an appropriate economic interpretation to each of its components.

| D1 | Di D2 O 5 7 02 9 03 8 765