The selling price given as = $ 15
The cost per CD is = $ 11
The total profit = Selling price - Cost
Total profit per CD = $ 15 - $ 11
Total profit per CD = $ 4
The markup on selling price is calculated as - Total profit ÷ Selling price × 100
Markup on selling price = $ 4 ÷ $ 15 × 100 =26.6666 % or 27 %.