A man gains 50% by selling an article for a certain price. If he sells it at double the price, the percentage of profit will be.
Choose the correct answer:  A) 130 %  B) 300 %  C) 150 %  D) 160 %  E) 170 %

Rationale: explanation : let the c . p . = x , then s . p . = ( 150 / 100 ) x = 3 x / 2 new s . p . = 2 ( 3 x / 2 ) = 3 x / 1 profit = 3 x / 1 - x = 3 x / 1 profit % = ( profit / c . p . ) * 100 = > ( 3 x / 1 ) * ( 1 / x ) * 100 = 300 % option b
Answer: B