The paper mill feeds a downstream box mill. The box mill's profit from each additional unit of boxes declines from $30 to $3. It costs the paper mill $9.50 to produce enough paper for one box. If the paper mill sets the paper price, it will maximize total profits by setting the price equal to the box mill's marginal profit from each additional box. At this price, company profits will be maximized. If the paper mill must transfer paper at its marginal cost of $9.50, the box mill will demand 10 units of paper, leading to total company profits of $24.