Thu 8 Dec, 2016 01:14 pm
3 death row inmates were given a hat on which a number between 1 and 3 (any possible combination of hats' number is possible - 112, 332, 111, 121, etc.)
Each were given a chance to guess the number on it's hat, when he sees the number on the two others.
Any communication between them is prohibited of course, and the only thing they know of each other is the number on the others' hat.
Which strategy the 3 should come up with, in order for at least one of them will be able to guess the number on it's hat correctly?
Each assumes the sum of the three numbers is equivalent to a different value (0, 1, or 2) modulo 3 and calculates his guess such that the sum will satisfy his assumption. Exactly one of them will be correct.