Some months back, this year, I was walking through the Central Park in New York. I saw an intelligent looking little boy playing all by himself on the grass. I decided to talk to him and just as an excuse to start the conversation I asked him his age. A mischievous glint flickered in his eyes and he replied, “Two days back I was ten years old, and next year I shall be thirteen. If you know what is today you will be able to figure out my birthday and that will give you my age”. I looked at him bewildered. How old was the boy?