An oldie, but a goodie

Here's an old logic problem about old men:

Three old wise men are sleeping peacefully under a tree, dreaming of erotic equations, when along comes that brat Terence. Terence procedes to paint each wise man's face purpley-red with beet juice, just for the hell of it. What a dirty bottom feeder. Anyways, as Terence beats a quiet retreat, the three wise men wake up and look at each other's faces. Pure hilarity ensues, as they all start laughing at one another. Terence snickers menacingly in the background, but that's beside point. The suddenly, one of the wise men stops laughing and says "Aw crap, I must have red on my face, too!".

The question is: how did he know?!?

(BTW, the traditional answer involves logic deduction.)

if one of the men had beet on his face then two of the men would laugh but only 2.

if two of the man had beet on their face then all of the men would be laughing but only looking at the two men with beet on their face, as all the men are laughing and looking at each other when they do this then all of them must have beet on their face.

Originally posted by kcams
if one of the men had beet on his face then two of the men would laugh but only 2.

if two of the man had beet on their face then all of the men would be laughing but only looking at the two men with beet on their face, as all the men are laughing and looking at each other when they do this then all of them must have beet on their face.

Sorry, I should have pointed out that none of the wise men can see their own face.

Also, if anyone has beet on their face then all three wise men would laugh, mostly because they're jerks. If a wise man saw another wise man laughing and looking at him, he would consider it convivial.

So I guess I'm saying that your solution is a common sense one, but doesn't logically answer the question, and it's not the one I'm looking for.

If only one wise man had beet on his face, then he wouldn't be laughing. So wise man C (the one who correctly deduced his face had been.. beet-en? beeted?) realized that both A and B knew this. If only A and B had had beat on their faces, and C didn't, A and/or B would have soon realized that the other of them is laughing, which means they must have beet on their face. Because of this, C realized that, because A and B didn't realize they had beet on their faces, he must have beet on his face or else one would realize the other shouldn't be laughing.

If that made any sense... hard to explain for me :\ Nice puzzle, by the way, it took some thinking to get.

Originally posted by BTBasham
If only one wise man had beet on his face, then he wouldn't be laughing. So wise man C (the one who correctly deduced his face had been.. beet-en? beeted?) realized that both A and B knew this. If only A and B had had beat on their faces, and C didn't, A and/or B would have soon realized that the other of them is laughing, which means they must have beet ...[text shortened]... e any sense... hard to explain for me :\ Nice puzzle, by the way, it took some thinking to get.

Excellent. That is the solution I was looking for.