Raise our Conscience against the Killing of RTI Activists

Thursday, April 22, 2010

Good Puzzle

In a Buddhist monastery there are N no. of monks and value of N is known to every monk. They have a head monk who does not belong to the N. One night the head monk puts a mark on heads of X number of monks out of N and the X is known only to head monk.Everybody knows X is not equal to 0. No form of communication is allowed between monks of monastery. The only time every body can  gather together is during lunch time. The head monk has told them that whoever understands that there is a dot in their head should not come for lunch from the next day onwards. How many days will the X monks take to realize that there is a dot in their head? How?

Answers are expected as comments.


  1. If there are X monks, all will leave together at the end of X days.
    Say X=1, So the one with head mark will see that nobody else is having the mark.Since X=0, he will understand tht its he is the one and only one and will leave.

    If X=2, First day both the guys with mark will think that the other one is the only one with mark.So both will turn up on second day as well. Then they will realise there is one more with head mark and will leave.

    and so on...Nice to have studied Mathematical Induction in Pre-Degree classes !!!!