A man sells an article at a profit of 25%. If he had bought it at 20% less and sold it for Rs.8.40 less, he would have gained 30%. Find the cost of the article.	Choose the correct answer
A) 30  B) 40  C) 50  D) 60  E) 70

Rationale: "let c . p = 100 gain = 25 % s . p = 125 supposed c . p = 80 gain = 30 % s . p = ( 130 * 80 ) / 100 = 104 diff = ( 125 - 104 ) = 21 diff 21 when c . p = 100 then diff 8.40 when c . p = ( 100 * 8.40 ) / 21 = 40 answer : b"
Answer: B