Lisa Division is currently purchasing a part from an outside supplier. The company's Great Division, which has excess capacity, makes and sells this part for external customers at a variable cost of $20 and a selling price of $32. If Great begins sales to Flow, it will use the general minimum transfer-pricing rule and it will be able to reduce variable cost on internal transfers by $4. If sales to outsiders will not be affected, Great would use a minimum transfer price of?