A fruit seller gives 10% discount and sells 15 apples per dozen to a customer. If he still ends up making a 20% profit on apples, how much % above the cost price are the apples listed? A 33.33% B 50% C 66.67% D 80 %

Let the CP of one dozen be 100. For every 12 apples, 3 apples are free. So, cost price of one dozen will be 125. He is making a profit of 20%. So, selling price of one dozen apples = 150. This is after a discount of 10% on marked price. So, MP = 166.67. So, 66.67% more than the CP.