The cost price of an article is 64% of the marked price. Calculate the gain percent after allowing a discount of 18%?
Choose the correct choice from the following choices.
A) 37.5 %
B) 48 %
C) 50.5 %
D) 28.125 %
E) 56 %

Rationale: "explanation : let marked price = rs . 100 . then , c . p . = rs . 64 , s . p . = rs . 82 gain % = 18 / 64 * 100 = 28.125 % . answer : option d"
Answer: D