Rivers Industries produces and sells electronic sound equipment. The company has production capacity of 20,000 units and currently production schedule is for 18,000 units. Each unit has a selling price of $25, variable product cost of $15, and variable selling cost of $2. Another division wishes to purchase 500 units. If Rivers sells the units to the other division, it will avoid $1 of the variable selling costs. What is the minimum transfer price that will maximize corporate profits