A trader cheats both his supplier and customer by using faulty weights. When he buys from the supplier, he takes 10% more than the indicated weight. When he sells to his customer, he gives the customer a weight such that 10% of that is added to the weight, the weight claimed by the trader is obtained. If he charges the cost price of the weight that he claims, find his profit percentage.  Choose the correct choice from the following choices:
A) 20 %
B) 21 %
C) 21.33 %
D) 22.109 %
E) 23 %

Rationale: "lets say the indicated weight is x for $ 10 but the trader actually get 1.1 x for $ 10 now he tells to the customer that its 1.1 ( 1.1 x ) = 1.21 x and charges the price accordingly i . e . 1.21 x * 10 / x = 12.1 so profit % = ( 12.1 - 10 ) / 10 = 0.21 = 21 % answer : b"
Answer: B