I got only two correct answers for this puzzle – one of which is from Tishyaa Chaudhry, who is one of the most amazing puzzlers amongst kids I have come across. Well done Tishyaa.

There are two good solutions to the puzzle, one of which requires the knowledge of Combinatorics. I have outlined both the solutions in the link here:

http://www.educreations.com/lesson/view/solution-to-puzzle-12/7125879/?s=cNI3nq&ref=link

Hope you enjoyed this one.