A retailer marks her goods in such a way that the profit made by selling 50 articles is equal to the selling price of 20 articles. What is the percentage of profit made by the retailer?
Select: A) 66.67 % B) 33.33 % C) 40 % D) 25 % E) 20 %

Rationale: let cost price = x profit = y selling price = x + y 50 y = 20 ( x + y ) 30 y = 20 x percentage profit = y / x ∗ 100 = 20 / 30 ∗ 100 = 66.667 answer = a
Answer: A