A shop owner professes to sell his articles at certain cost price but he uses false weights with which he cheats by 10% while buying and by 10% while selling. What is his percentage profit?  Pick one:	A) 10.22 %	B) 20.22 %	C) 21.22 %	D) 22.22 %	E) ca n ' t be calculated

Rationale: "the owner buys 100 kg but actually gets 110 kg ; the owner sells 100 kg but actually gives 90 kg ; profit : ( 110 - 90 ) / 90 * 100 = ~ 22.22 % answer : d ."
Answer: D