A shop owner professes to sell his articles at certain cost price but he uses false weights with which he cheats by 30% 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) 30%  E) Can't be calculated
The owner buys 100kg but actually gets 130kg;   The owner sells 100kg but actually gives 90kg;   Profit: (130-90)/90*100=30%   Answer: 30%.
<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 30% while buying and by 10% while selling. What is his percentage profit?