There's a classic logic puzzle in which a person must take a fork in the road, one of which is safe, but the other is a deadly trap. Two men guard the fork, one of which always lies, but the other always tells the truth. The person gets to ask one question in order to determine which path is the safe one.
Mathematician Raymond Smullyan has added another dimension to this puzzle. See if you can figure it out:
Link via Marginal Revolution | Raymond Smullyan
UPDATE 3/18/10: Here's the solution.
Mathematician Raymond Smullyan has added another dimension to this puzzle. See if you can figure it out:
There are three guardians, A, B and C. Their names are Knight, Knave and Chaos. Knight always speaks truly, Knave always lies. Chaos tossed a coin this morning to decide whether today he would behave like Knight or like Knave.
Your task is simple: ask three yes-no questions, each of a single guardian, and determine which is Knight, which is Knave, and which is Chaos. There is, alas, a complication: the guardians understand English but will answer in the local language, in which “Da” means yes and “Ja” means no. Or possibly “Ja” means yes and “Da” means no – you cannot remember.
Link via Marginal Revolution | Raymond Smullyan
UPDATE 3/18/10: Here's the solution.
Comments (39)
If A answers “ja”, he’s Chaos. Then ask Guardian B, “If I asked you, “Are you Knight?”, would you say “ja”?”. The answer is “ja” if B is Knight, and either way the problem is now solved.
If A answers “da”, he’s either Knight or Knave. So ask him instead, “If I asked you, “Are you Knight?”, would you say “ja”?” If the answer is “ja” he’s Knight; otherwise he is Knave.
So, now, ask him “If I asked you, “Is guardian B Chaos”, would you say “ja”?” If he answers “ja”, B is Chaos, and C is the opposite of A. If he answers “da” then C is Chaos and B is the opposite of A.
Has anyone actually found a solution?
Yeah it's important to have a sense of humor, but really, isn't this rather childish? How are you going to explain this to the kids? Oh, they'll remember this moment, when the whole town's signs went silly. They'll remember.
And the drunk drivers will be saying "Oh, I thought they were joke signs, not really serious about us actually reading them and understanding that they're not jokes."
Nice.
It's fine to take it lightly, but a cop showing up even every now and again gets the message across pretty quick "don't cruise through this stop sign". And if that doesn't quite work the cost of the ticket for a moving violation as well as the added points to your insurance will speak volumes.
I´m not liying...
If was done just for the fun of it though, then I'm for it.
dude, when every pompously official-sounding message of government already has the credibility of an arsonist giving fire-safety tips, you oughta think about the benefits of cutting through the clutter to reclaim some little bit of attention. Or you could just take a breath and take what seems like a much-needed vacation.
And the possibility of people interpreting the stop signs themselves as fakes is too big a risk to take with people's lives.
"I'm sorry I ran over your daughter, but isn't that a funny sign?"
Reading comprehension suffers yet another in a long series of slaps in the face.