A shop owner professes to sell his articles at certain cost price but he uses false weights with which he cheats by 12% while buying and by 30% 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) 60 %  E) ca n ' t be calculated

Rationale: "the owner buys 100 kg but actually gets 112 kg ; the owner sells 100 kg but actually gives 70 kg ; profit : ( 112 - 70 ) / 70 * 100 = ~ 60 % answer : d ."
Answer: D