A shop owner sells 15mtr of cloth and gains SP of 10 mtrs. Find the gain %?  Choose the correct choice from the following answers:
A) 30 % B) 40 % C) 50 % D) 100 % E) 200 %

Rationale: "here , selling price of 10 m cloth is obtained as profit . profit of 10 m cloth = ( s . p . of 15 m cloth ) – ( c . p . of 15 m cloth ) selling price of 5 m cloth = selling price of 15 m of cloth let cost of each metre be rs . 100 . therefore , cost price of 5 m cloth = rs . 500 and s . p . of 5 m cloth = rs . rs . 1500 profit % = 1000 / 500 × 100 = 200 % profit of 200 % was made by the merchant . e"
Answer: E