The ratio between the sale price and the cost price of an article is 7:5. What is the ratio between the profit and the cost price of that article? Choose the correct answer.
A) 2 : 8
B) 2 : 1
C) 2 : 2
D) 2 : 4
E) 2 : 5

Rationale: "explanation : let c . p . = rs . 5 x and s . p . = rs . 7 x . then , gain = rs . 2 x required ratio = 2 x : 5 x = 2 : 5 answer : e"
Answer: E