A transportation company contracts with farmers in Nebraska, Kansas, Illinois, and Missouri for monthly wheat shipments. They pick up wheats at the farms and ship mostly by truck $($and sometimes by rail$)$ to its sorting and distribution centers in Maryland, New Mexico, and Kentucky. At these centers the wheat is cleaned, rejects are discarded, and the rest is sorted according to quality. They are then shipped to combination plants and distribution centers inNew Hampsire, lowa, Florida, and Arizona, where the company produces a variety of wheat product and distributes them to stores. Exceptions are the Maryland distribution center, which will accept wheat only from farms in Nebraska, Kansas, and Missouri. In addition, New Hampshire plant does not accept shipments from New Mexico, lowa does not accept shipments from Maryland, and Florida does not accept shipments from Kentucky.

Following are summaries of the shipping costs from the farms to the distribution centers and the processing and shipping costs from the distribution centers to the plants, as well as the available monthly supply at each farm, the processing capacity at the distribution centers, and the final demand at the plants $($in bushels$)$: