A Puzzle

Wanna drive away the mid-noon post-lunch lethargy and the Monday-morning blues? Try this puzzle:

A shop sells one chocolate for one Rupee each.
You can exchange 3 wrappers for 1 chocolate.
If you have Rs. 15, how many chocolates can you get?

Oh, and BTW, I am told that 90% people answer it wrong.

So give it a try. I will post the answer tomorrow.