Windsor 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. Books Movies Magazines

Selling price $10 $15 $6 (Books, Movies, Magazines)

Variable cost/unit 3 9 1 (Books, Movies, Magazines)

In addition, Windsor incurs facility and administrative costs that average $28,520 per month.

Find the weighted-average contribution margin $ /per unit