Rohan, a 7 year old boy, was really fond of the chocolates called "Chocoberries". He asked his Mrs. Mother to give him some money to buy his favorite chocolates. His Mrs. Mother gave him Rs 45. He went to the shopkeeper and asked, "how much is one chocoberry for?". The shopkeeper said, Rs 3 for one chocolate. Also, if you give me the wrappers of three chocoberries, I will give you one for for the exchange.

In total, how many chocoberries could Rohan eat?

22.

He can buy 15 chocolates at first from the 45 bucks that he has. Then further, he can exchange the 15 rappers to get 5 more. Then he can return 3 rappers of the 5 to get one more chocolate, and in the end use the wrapper from this one alongwith the 2 left with him to get one more. 15+5+1+1= 22.