You and two other people have numbers written on your foreheads. You are all told that the three numbers are primes and that they form the sides of a triangle with a prime perimeter. You see 5 and 7 on the other two heads and both of the other people agree that they cannot deduce the number on their own foreheads.

What is the number written on your forehead?

(In reply to re(2): centering the point by armando)

Thank tou, Armando, for your words.

But if you read the comment of emdad, where he concludes that I could have a 3, you'll see that the discussion is far from finishing.

As I answer to him, I THROW THE TOWELL !!!

But I'm convinced that the unique solution is 11, reasoning like I stated, and, until now, no one could find anything to "knock it down".  

 

Posted by pcbouhid on 2005-03-15 15:49:59