Old 09-17-2014, 12:42 AM
koren koren is offline
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Default “the robots enigma”


The basis of this puzzle is Raymond’s Smullyan “Three gods puzzle” but with smaller amount of base data, making it more difficult – more difficult than “The hardest logic puzzle ever…” As you can see, there is an incentive – good luck!

"Three robots A, B, and C are called, in some order, True - (T), False (F) and Random (R). (T) is programmed to speaks truly, (F) – falsely, but whether (R) speaks truly or falsely is a completely random matter.
The robots can answer only YES or NO. Each robot is equipped with two small lamps - red and white. When robot responds – the red light lights up, but you do not know he said YES or NO. When there is no answer – lights up the white light.
Your task is to determine the identities of A, B, and C by asking no more than three questions; each question must be put to exactly one robot".
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Old 09-19-2014, 10:18 AM
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Betashadow Betashadow is offline
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Omg!! I have been at this for like the past 2 hours. The main catch is that the robots dont answer YES or NO. They simply indicate that they know the answer. Lets hope I get the answer soon...
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Old 09-19-2014, 01:48 PM
koren koren is offline
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You're right, good luck.
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Old 04-14-2015, 05:52 PM
lexxns lexxns is offline
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Default Possible Solution

Hi i'm new to this site hence why iv'e just seen this puzzle, but I think I have a solution. Please correct me if I am wrong.

If you ask robot 1 whether both of the other 2 would answer a question truthfully (T) would answer no since (F) will lie - therefore will show a red light and (R) will also show a red light since it must answer.
(F) would not answer the question since (T) would answer truthfully but (R) may or may not, so this has no true or false answer. - White light.

This same question to robot 2 finds for certain the location of (F), since if there are no white lights yet, robot 3 must be (F)

if (F) is either robot 1 or 2, asking robot 3 whether the other of 1 or 2 would answer a question truthfully gives white if 3 is (T) but red if 3 is (R)

if (F) is robot 3 however asking it whether robot 1 (or 2) would answer a question truthfully gives a red light if robot 1 was (T) or a white light if it was (R) - giving the final solution.

Hopefully I haven't missed anything crucial in all this.
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Old 04-15-2015, 08:16 AM
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Chezzik Chezzik is offline
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lexxns reply is a little bit hard to follow, but I believe it is completely correct.
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