If the cost price is 80% of the selling price, then what is the profit percent?  Choose the correct choice
A) 5 %  B) 11 %  C) 13 %  D) 25 %  E) 19 %

Rationale: "let s . p . = $ 100 c . p . = $ 80 profit = $ 20 profit % = 20 / 80 * 100 = 25 / 6 = 25 % answer is d"
Answer: D