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Prime Perimeter (Posted on 2005-03-11) Difficulty: 3 of 5

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?

See The Solution Submitted by Erik O.    
Rating: 2.8235 (17 votes)

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unique? | Comment 47 of 89 |

Unique, a word that makes this problem quite interesting. 

I believe unless we say that "u n 2 other people have unique numbers..." that there is not a unique solution.  There is that crazy word again.

But if it happens to be 11. Let me say I was the first to post it.  Which really does not mean much.  But is a source of pride to me since  that would be a unique occurence.

Remember however, that this is not a contest. You get no points for answering correctly or first, nor does it count towards any sort of rank. So there is no real need to post your solution if it has already been posted a few times. The satisfaction of knowing you solved the puzzle ought to be a sufficient reward.

I think that is a bunch of malarkey(sp?)  You all can't handle my crazy skills, I got game, Yo YO, don't make me open my can on you, I got all kindza smack to talk.

  Posted by john on 2005-03-14 15:35:08
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