Last month, PeeWee Company manufactured 20,000 units and sold 18,000 of these units at a price of $8.00 per unit. Manufacturing costs consisted of direct labor, $30,000; direct materials, $32,000; variable manufacturing overhead, $3,600; fixed manufacturing overhead, $21,600. Selling and administrative costs totaled $24,000.
Assume PeeWee uses variable costing? How much would the company's contribution margin increase if sales increased 10%?