It is easy to see that this would save £4 for every unit of capacity so
transferred. This would be effected by one unit less from Warehouse 3 to Customer 1 (saving
£7) and one unit more from Warehouse 1 to Customer 1 (costing an extra £3). The same saving
of £4 is arrived at by multiplying the u values by the respective changes in supply. The change
in cost, C is given by