Tamarisk sells books, movies, and magazines to a wide customer base. In a typical month, about 40% of its sales volume is from books, 40% from movies, and 20% from magazines. The selling price and cost information for each of these product categories is as follows. In addition, Tamarisk incurs facility and administrative costs that average $28,000 per month. (a) Your answer is incorrect. Find the weighted-average contribution margin per unit for this company. (Round answer to 2 decimal places, e.g. 15.25.) Weighted-average contribution margin $ per unit