If the cost price of 81 chocolates is equal to the selling price of 45 chocolates, the gain percent is : Choose the correct option
A) 80 %  B) 85 %  C) 82 %  D) 70 %  E) 75 %

Rationale: "explanation : solution : let c . p . of each chocolate be re . 1 . then , c . p . of 45 chocolates = rs . 45 ; s . p . of 45 chocolates = rs . 81 . . ' . gain % = 36 * 100 / 45 = 80 % answer : a"
Answer: A