A shop owner professes to sell his articles at certain cost price but he uses false weights with which he cheats by 20% while buying and by 10% while selling. What is his percentage profit? Choose the correct choice from the following choices:
A) 10.22%
B) 20.22%
C) 21.22%
D) 20%
E) Can't be calculated
The owner buys 100kg but actually gets 120kg;   The owner sells 100kg but actually gives 90kg;   Profit: (120-90)/90*100=20%   Answer: 20%.
<result>D</result>
A shop owner professes to sell his articles at certain cost price but he uses false weights with which he cheats by 20% while buying and by 10% while selling. What is his percentage profit?