In a transportation problem, which constraints must be satisfied?

In a transportation problem, which constraints must be satisfied?

• A. Supply constraints for each supplier and demand constraints for each consumer
• B. Only supply constraints
• C. Only demand constraints
• D. No constraints on demand

Answer: (A)

In a transportation problem, you must respect both how much each supplier can ship and how much each consumer requires. For every supplier, the total amount shipped out cannot exceed its available supply (and, when all supply is used, equals it). For every consumer, the total amount received must meet its demand (and, when all demand is satisfied, equals it). When total supply equals total demand, these become equalities: the shipments from each supplier sum to its supply, and the shipments to each consumer sum to its demand. This combination of supply and demand constraints defines the feasible shipments. If you only had supply constraints, you could leave some destinations unmet. If you only had demand constraints, you could violate the suppliers’ capacities. And having no constraint on demand would permit unrealistic, unlimited shipments.

In a transportation problem, you must respect both how much each supplier can ship and how much each consumer requires. For every supplier, the total amount shipped out cannot exceed its available supply (and, when all supply is used, equals it). For every consumer, the total amount received must meet its demand (and, when all demand is satisfied, equals it). When total supply equals total demand, these become equalities: the shipments from each supplier sum to its supply, and the shipments to each consumer sum to its demand. This combination of supply and demand constraints defines the feasible shipments.

If you only had supply constraints, you could leave some destinations unmet. If you only had demand constraints, you could violate the suppliers’ capacities. And having no constraint on demand would permit unrealistic, unlimited shipments.