A reduction of 30% in the price of oil enables a house wife to obtain 9 kgs more for Rs.1800, what is the reduced price for kg?  Choose the correct choice from the following choices
A) rs . 55  B) rs . 60  C) rs . 65  D) rs . 70  E) rs . 75

Rationale: "explanation : 1800 * ( 30 / 100 ) = 540 - - - - 9 ? - - - - 1 = > rs . 60 answer : b"
Answer: B