Additional considerations include the investment in inventories, the number of sales personnel, the skills and training of sales personnel, and the degree of substitutability between the types of items. This problem could also be addressed on a unit basis. Suppose one designer item is displayed and sold in a given time period. Sold in the same period? Moderate priced items displayed = 4/3 x designer items displayed = 4/3 x 1 = 1 1/3 For each item displayed, 1 1/2 moderately priced items would be sold in the same time period that 1 designer item is sold. Why?