The HARDEST Logic Puzzle Ever (Simpler Version): Two Doors To Freedom Riddle
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- เผยแพร่เมื่อ 11 มี.ค. 2017
- An evil warden holds you prisoner, but offers you a chance to escape. There are 3 doors A, B, and C. Two of the doors lead to freedom and the third door leads to lifetime imprisonment, but you do not which door is what type. You are allowed to point to a door and ask a single yes-no question to the warden. If you point to a door that leads to freedom, the warden does answer your question truthfully. But if you point to the door that leads to imprisonment, the warden answers your question randomly, either saying "yes" or "no" by chance. Can you think of a question and figure out a way to escape for sure?
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Source
This puzzle is a variation of the ace and jacks problem, a preliminary problem in the paper about “the hardest logic puzzle ever.” Boolos, George (1996). “The hardest logic puzzle ever”. The Harvard Review of Philosophy. 6: 62-65. www.hcs.harvard.edu/~hrp/issue...
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I forgot to put the source in the video description originally. This puzzle is a variation of the ace and jacks problem, a preliminary problem in the paper about “the hardest logic puzzle ever.” Boolos, George (1996). “The hardest logic puzzle ever”. The Harvard Review of Philosophy. 6: 62-65. www.hcs.harvard.edu/~hrp/issues/1996/Boolos.pdf
TED-Ed did a video about "the hardest logic puzzle ever" they called "the three gods riddle." th-cam.com/video/LKvjIsyYng8/w-d-xo.html
You're meant to assume that you can only choose one door to open, and the question that you ask is supposed to help you determine which one to choose. Hope this helps you understand!
MindYourDecisions I figured it out :D
This shows that the warden is not evil enough; 66.6 % by chance and 100% by logic.
Another answer- Point A and ask - Do A and B lead to freedom? If YES choose B, if NO choose C.
MindYourDecisions
My single question:
If I were to ask you 100 times, as to whether this door could lead me to freedom, what would your answer be?
If the door could lead me to freedom, the answer would be a resounding “Yes”.
If the door could lead me to life-imprisonment, his random answering technique, based on statistics, should produce a 50-50 probability.
Therefore logically, his answer would neither be a resounding Yes, nor No.
Technically, I do abide by all the rules, of this logical puzzle, and statistical theory.
If he is an evil warden, all the doors would lead to imprisonment and the whole ordeal would have been a cruel joke.
Actually that is what imo happens here.
He gave him false hope in saying that there are 2 freedom doors and 1 imprisonment.
When you ask if B leads to freedom. Hell say "Yes". (spoiler: its a lie) Since you thought that if he says "Yes" then the B door is freedom youll choose B door and you got imprisoned.
Since if door A lies about Door B leading to freedom => Door A is imprisonment itself but also since he lied about B leading to freedom, B is imprisonment as well.
So in the "Yes" (Lie) scenario only C would be freedom (or at least possibly could be) and since you chose B he got you because you believe a lie in the very beginning. If Yes is a lie there are 2 imprisonments and only 1 freedom (and thats only maybe).
@@Dark_Voice he will make you think you chose the wrong door, but all of them lead to hell
Cool plot twist
No. You have your "if and then" backwards. He's also evil if you ask if door A leads to freedom, he says yes, and you're imprisoned for life (as possible in the riddle). The Warden is evil regardless.
so... america?
Hey thanks man ii was stuck in this situation a while back but then I remembered your video and now I'm free
Oh that kind of situation exist?
@@drenz1523 Where you don't even need to ask the question, considering the odd of losing!
🤣🤣🤣
@@RGC_animation bruh never take a 2/3 odd on something important. Thats to much risk. This situation is just for the puzzle, but pls dont risk anything important on a 2/3 chance. Unless you have to.
@@alex2005z Too late!
thought for a sec it'd be the "lions who haven't eaten in 3 years" riddle lol
Same
So, the rotting pile of lion's bones puzzle 😂
all riddles from 7 second riddles and bright side are crap these logic puzzles and stuff are the good ones
@@RichRBLX i agree
Oh. That's a simple solution.
I envisioned asking something like a paradoxical question, or something he can't know the answer to like "is the third character of my email password a 'g'?"
If he answers yes or no, then it's the imprisonment door. If it's a freedom door he'll answer "truthfully": "I don't know" or "there is no answer."
In these sorts of riddles I always imagine the warden is omniscient.
@@Eggscargot true-but non-standard answers are always fun
You thought that was simple? I said ask every door if they’re the door they’re being said to be many times and whichever changes answer is the incorrect one
Doesn't follow the rules, you have to ask a yes-no question
@@Mustard0981 “is the third character of my email a g” *IS* a yes or no answer.
wtf kinda warden gives you a 2/3 chance for escape, then lets you ask a question?
the same dumbass warden who lets you add that door to the question without mentioning it verbally.
@@EliteGeeks and then lets you escape freely if you figure it out
The same warden who is bound to answer any question truthfully as long as you're pointing to the door that leads to freedom. These logic problems have many logical fallacies to be called the perfect logic puzzle.
Chaotic evil
@@manah2882 it is a logical puzzle. Risking is a 2/3 chance. This is 1/1
This reminds me of the riddle concerning two doors (one leading to freedom, the other to certain death / imprisonment, but you don't know which is which) and two guards (one always answers truthfully, the other always lies, but again you don't know which).
In that scenario, the best question is apparently "If I asked the other guard which door leads to freedom, what would he say?", then you take the _other_ door, as the question guarantees you'll get the wrong answer.
"in which of these two directions do you live?"
That makes sense.
the riddle reminds me of the three alien gods riddle on tededs channel
What about something like
“Does 2 + 2 = 4?”
Then if they said use, take the door and if not, the other door
@@teletummy
U only can ask 1 question and the guard didnt stand beside the door
So if you already know which guard is the liar or truthfully, u cant ask more question
I really liked this problem. At first, I thought how can a random answer provide information but then I realized that the answer was not always random. And this small difference allows for a solution. In my mind, I created a table instead of a tree.
Door A Door B Door C Answer
Freedom Freedom Prison Yes
Freedom Prison Freedom No
Prison Freedom Freedom Yes or No
Of course, the result is the same - yes pick door B, no pick door C.
What donyou mean always B it depends on the question. Right. My version is similar to Oresh except I point point a door and ask does the door next to it lead to prison? If he says yes pick the third door i.e. C if I point to A and ask abiut B, if he says No pick B the door I ask about..see what I mean?
I'm almost positive that this will actually happen to me at some point, and I won't remember how this works.
The "evil" warden will let you use his laptop to look it up on TH-cam
My first thought was to ask a paradox question (something like "will you say no?") so he'll be stumped if he tries to tell the truth
This was also my thought, I think it seems a valid solution!
That was also my first thought, but it doesn’t work.
@@robinguillard7042 it isn’t.
If you can ask a yes/no question that the warden has no way of knowing the answer to, then their truthful answer should be something like, "I don't know." If they answer yes or no in that situation, the other doors should lead to freedom.
@@drwaffle7781 the rules clearly state that the lying warden can answer any question yes or no randomly.
I thought about pointing at one door and asking if his answer will be no.
If it leads to freedom he can not answer truthfully and thus will say nothing,
if he answers, regardless of the answer it must be a random answer and thus the other two doors must lead to freedom.
I've thought about something similiar, but we can't be sure what the author meant by a "yes or no question".
Pretty sure a "yes no question" implies that the answers may only be yes or no and if your question can have no answer then it's not a "yes no question". Now you would be able to ask your question but even if you were pointing at the bad door you'd get no answer since you're question didn't follow the rules.
AlekG Tho it has "no" answer 😂😂
actually the part "If it leads to freedom he can not answer truthfully and thus will say nothing," is wrong. It's stated that he will answer truthfully, so in this case it all just wouldn't make sense. I think it's reasonable that when we are trying to solve the riddle, we pick such definition of "a yes or no question", that the riddle makes sense, thank you.
Okay that makes sense to me. Thank you for this answer.
He ain't evil if he offers a chance to escape .. he's just bored lmao
My awnser:
I would point to A and ask if either A or B leads to inprisonment.
If he says Yes, choose C.
If he says No, choose B.
because if he says No either C is inprisonment or he is lying thus A being inprisonment.
Always fun!
Mine is also a genuine non paradox awnser, not like the others :P
excellent answer! also, are you a pewdiepie conscript?
Teemu Rantanen yeah, sort-of
The TH-cam Addict nice solution :)
that was what my intuition said to me.
Omg this just happened to me. I remember watching this before and came back to thank you cause I probably would have died if I hadnt watched this
Susheel G probability of 33.33%
Everyone is saying the warden is evil but it's actually really nice of him to give you at least a 2/3rds chance of walking away free
Without watching rest of video here's my solution:
Point to door A and ask "do door A and B lead to freedom?"
If warden answer Yes go through door B (either A or C lead to imprisonment)
If warden answers No go through door C (Door A leads to imprisonment)
you literally just watched the video
@@No_king1143 He must be ded now
@@gautamkelkar2132 F for them
That was my solution too, though I would add that if the warden answers "No" and he's being truthful, then door B leads to imprisonment. Only when he's being random would door A lead to imprisonment.
@@No_king1143 That is another puzzle; did he take a hidden door and travel back in time to answer the question before he read it? 😉 😀 😀
That took me a bit, but it was clever. I thought, "I don't want to have to choose to go through the random one" and was able to work it out but it was stimulating. Nice
*Everyone putting their logic*
Me - "are you allowed to peek through the door?"
"Can you think of a a question and figure out how to escape for sure?"
Me- No.
I came up with, point at door 1 and ask "does the door i'm pointing at have the same outcome as door 2?"
if he says yes, you pick door 2 (because if it was the truth then door 2 will work, and if he says no then door 1 was the imprisonment door, so door 2 has to lead to freedom)
if he says no you pick door 3 (because if it was the truth then either door 1 or 2 are the imprisonment door, and if it was a lie then door 1 or 2 have to lead to imprisonment)
*points to b* does door b lead to freedom?
-Yes
Aha!
*walks in and dies*
It says imprisonment, not fatal organ failure
@@drenz1523 no, its freedom. freedom from your mortal bounds
@@WaterDroplet02 no i said the bad one not freedom
"Is my next coin flip going to be heads?"
The honest answer would be "I don't know", therefore the door is safe.
An answer of yes or no is just as random as the coin flip, therefore the door is not safe.
I don't know could be the answer he chooses at random.
@@AlDunbar It said if he chooses randomly, it would be either "yes" or "no"
@@bg6b7bft sorry I didn't read tge riddle carefully enough. Thanks
What is the point in pointing at door A?
The door you point at indicates whether the Warden is truthful or just answers randomly.
It doesn't matter which door you point at as long as you are asking about one of the other two doors. For example, you could point at Door C and ask about either A or B. As long as you don't go through the door you pointed at and you trust the answer as true.
The reason you can trust the answer as true is because, if it isn't true, then the door you are pointing at is the imprisonment door. OTOH, if you are not pointing at the imprisonment door, then he will tell you the truth.
Before I see the answer this is my solution:
Point to the middle door and ask “Does the door on the left lead me to freedom”
If the answer is yes go through the left door, otherwise go through the right one
If the door in the middle was freedom then he will tell you if the door is safe, or in the other hand which one is not, leaving u with the right door which would be guaranteed to have freedom
You can notice how in neither of those two cases we go through the middle door, if the middle door is imprisonment no matter what answer we gat we won’t go through that one but the freedom ones
Edit: Nailed it! I didn’t do the same order as him but it doesn’t matter. Also I solved this in like 5-10 seconds I’m smart :)
I did the same except asked if it leads to imprisonment.
Hi pressh , this kept me awake hours last night , I finally understood it thank you
Beautiful puzzle! Love it! ❤
Im glad i figured this one out, since I am not really good in these asking-question-riddles. But I think it would have been better, if you would have presented the logic the other way around:
If the warden says Yes, then door B is safe, regardless if the warden is saying it truthfully or not. Because if he is, then door B is definitly safe. If he chooses randomly then it is also safe to go trough B. If he answers No then you go trough door c with the same logic.
You did showed the Logic correctly, but for me it would made more sense if you switched it around like this. (Sorry for my bad english)
Point to the any of the doors and ask "how much will be 2+2?" If he answers "4" - pick this door. If he answers "yes" or "no" - pick another.
Dang this was my exact solution as well!
The question should be yes-no question as mentioned in the problem
I've been stumped by logic puzzles before, but I'm happy to say I was able to work this one out in less than a minute and I didn't even have to break out the pencil and paper. My thought process was, "would pointing to a door and asking if it led to freedom help? No? What about pointing to a door and asking if _another_ door would lead to freedom?" Then it was just a matter of playing through all of the scenarios.
yes me too, very satisfying
Yeeeeah :) took me roughly 45 minutes but I did. I asked about door C (while pointing to A) but it is the same solution regardless.
I somehow intuited it after thinking of the doors as A,B,C instead of in grounded realistic terms.
Im sitting here trying to tame the thread of logic that flared in my mind which lead to me diagraming it out and getting the answer. Part of me understands but I feel I can understand it more. Annoying.
To put it another way:
The tree you drew is exactly that 'thread' but it feels too much like a map and less like I've traveled that land and KNOW it.
Here is my solution:
Point at door A and ask: "If door A was the one that leads to prison and I asked you: "do you work for government?" would you answer by yes?"
If he answered "yes" or "no", then A leads to prison and you go for door B or C.
If he didn't answer, go for door A.
If A did lead to prison, he could answer anything. So if it does not, by proposing what he would say if it did, he can answer anything.
@@weckar Yep. He's saying if theree was any answer at all, then you should go for door B or C. But if door A leads to freedom, he cannot answer yes or no, so he wouldn't answer at all.
He could say 'yes', because he COULD answer 'yes' in that scenario. And if you say 'would you DEFINITELY answer me yes?', he would say 'no' because he isn't sure.
I mean, it's already cheating a bit, but I don't think it's entirely sound.
There's another way to do this. Point to door A and ask if door B leads to a lifetime in prison. If he answers yes, then you go through door C because either he's telling the truth, in which case door B is the door to avoid, or he's lying, in which case door A is the door to avoid. If he says no, door B is a safe door, exit through door B since he can't be lying about it. The reason for this is that if he was lying, then only door C would lead to freedom, which would break the rules of the game.
There is one issue: if this warden is evil, why wouldn't he lie about the rules to the game? All of the doors probably lead to a life in prison and it's just a sick joke for him. If it wasn't, then he wouldn't truly be evil.
OK, so the interesting question for me is what is a general strategy for framing the appropriate question. A useful place to start is to assume that we're going to have to break it down into cases. There are only six cases: all combinations of yes/no and A/B/C being the door leading to imprisonment. Just drawing out the 2 x 3 grid and staring at it suggested to me that the question has to maximize the information being collected by asking something about a door other than the one being pointed to. Then start guessing questions and examining all the cases. The most obvious question is, "does that door lead to freedom?" With that question, an examination of the cases reveals that two of them are impossible, leading to the answer.
You point to any one door then flip a coin, covering it. Without revealing the coin, you ask the warden, "Did the coin come up heads?" If the warden answers that he doesn't know for sure, then you pointed to the freedom door. If the warden answers either yes or no, then the door you pointed to was the door of doom.
This is a wonderful answer. 👏
but what if he randomly answers I don't know. if the truthful one can say it why isn't it in the range of possibilities of the random one
@@Blockoumi To be more precise, you point to a door, and say "I'm going to flip a coin, and if it comes up heads then the freedom door is the one I pointed to." Then, you flip the coin, covering it, and ask the warden, "Did the coin come up heads?" If the warden answers that he doesn't know for sure, then you pointed to the freedom door. This corrected version makes the flip of the coin connected to the door. In the first version, the connection was only implied. No person can with certainty state how a coin has landed given that they can't see the result, so an honest person would have to say that they are not sure. A dishonest person would say emphatically one or the other outcomes.
@@noelnewlon 🤠👍
Basically, when you get a negative answer that's an indication that one of the two doors is bad. You take the third one.
When you get a positive answer, then that's a certain indication that the door you're asking about is good, even if you don't know if the door you're pointing is good or bad. Okay. Got it! Now my brain hurts 🤕 but I got it! 😂
Hint that won't give it away: The door you point to does not have to be directly related to the question you ask.
Then the warden has to be patient, because I need to watch this video in front of him to figure it out.
Alternatively, you can ask the warden a yes or no question he cannot possibly know the answer to.
Since, if you're pointing at a bad door, he must answer yes or no by chance, you can infer that the other two doors lead to freedom if he does so.
However, in the event that you are pointing at a good door, he cannot truthfully answer anything but "I don't know" or not answer at all.
I would assume this warden would either say that is a wasted question or make you ask a question that has a definitive answer.
Why are there so many evil wardens that will hold you as a captive :(
Or maybe you committed a terrible crime. And the warden is nice to give you a chance for redemption.
Glass half full.
Because of Beauty and the beast fanfic
Excellent riddle. Reminds me a little bit of the George Boolos "Hardest Puzzle Logic Puzzle Ever"
OR- , put a friendly arm around Wardens shoulder.. casually wave three fingers of one hand at _all three_ doors, and ask - ''Let me buy you a beer, buddy?'' ;)
My solution (not as good as OP's): Point to any door and ask "Will I get out of prison?"* If it's a freedom door he will have to truthfully say "I don't know." or not reply. If it's the prison door, he will definitely say "yes" or "no". If he says "I don't know" or nothing take that door. If he says "yes" or "no" take one of the other doors.
* You could also just ask any unknown question about the future like "Will I live to be 100?"
tubular618 it has to be a yes or no question
"Will I get out of prison" is definitely a yes or no question. It's just not one that anyone knows the answer to yet.
Saying "I don't know" doesn't tell you anything because the warden could lie if you pointed at the wrong door. The rules are it must be a yes or no answer so I think you would get life imprisonment by default.
Okay same logic, but I thought of asking the question does door A lead the same place as door B
Pose a logic puzzle, such as "Will you answer 'no' to this question?" If they can answer the question with a yes or a no, then that was the bad door and don't go through. Otherwise, go through the door you pointed to.
I didn't figure out the question until I was told but once I knew the right question I was able to work out all the logic in my head.
ANSWER: point to door A n ask warden "door B leads to life time imprisonment right?"
if he says "NO" -open door B
if he says "YES"- open door C
Yes this inverse answer is another distinct solution
Wow you watched the video good job man
When pointing to door A and asking whether door B leads to freedom, the warden's answer of yes or no may either be a truthful answer or a random answer.
If door A leads to freedom then the warden's answer will be truthful. If the answer is yes, this means that door B leads to freedom; if the answer is no then door C leads to freedom.
If door A leads to imprisonment then the warden's answer will be random. The answer of yes or no is irrelevant. Doors B and C have to lead to freedom.
We don't know whether door A leads to freedom or imprisonment so we don't know whether the warden's answer is truthful or random. Through studying the possible outcomes we can conclude that a yes answer will always indicate that door B leads to freedom and a no answer will always indicate that door C leads to freedom.
This is an extremely lenient warden. He gives you a 66% chance of living, AND allows you to ask a question to potentially gurantee your release? If logic was the only way out, then he should at least not give the person who doesn't use logic a full 66% chance of freedom.
67*
@@Smalllbuddy If you wanna be real technical it's 66.6666666~ repeating but does it rly matter?
Haha was kidding
My strategy was completely different, i'd point to a random door and ask "Is the awnser to this question no?" If he would awnser truthfully he couldn't give an awnser, so i know the door is safe, if he says yes or no then i know he awnsered randomly making it the unsafe door
I really need to start thinking outside the box more on these. It took me a while to realize the pattern.
If you point to any door (Door A is the example in the video) and ask if a different door (Door B) leads to freedom, whether Door A leads to freedom or imprisonment you can safely choose Door B if he says yes and Door C if he says no because whether he's telling the truth or not, if he says no, Door C is safe, and if he says yes, Door B is safe (because if he was answering randomly that means both are safe bc Door A leads to imprisonment)
I had guessed something outside of the box, which is to ask the warden a paradoxical question that if he answered honestly, he would have to concede it was not true or false. But if it was the bad door, he would say true or false - and it doesn’t matter which one, you know it’s the bad door because he answered at all. (The wording of the puzzle didn’t say the warden had to strictly answer yes/no, but just that he answered truthfully)
I came up with the same kind of thing:
My question was: If I walk through either one of the other 2 doors, will I be free?
Interesting Puzzle.
Ron and Sean were hostel friends both good at logic.
Once Ron was visiting Sean and during their conversation asked Sean ..... How old were Sean's three daughters.
Sean answered as follows:
The sum of the ages of my three daughters is 13.
The product of the ages is equal their hostel room number.
Ron says he is unable to guess the ages and needs one more clue.
On this Sean says My eldest daughter is sleeping upstairs.
On this Ron guesses all the three ages correctly what are their ages?
Answer: 2, 2 and 9.
I tough of : is this door and the one next to it are one good one bad? If answer its yes, puck the third door. If its no pick the door mext to it
I would be interested to hear what the strategy would be used if there was only ONE door to freedom, and TWO doors to imprisonment.
An interesting variation. Never seen this one before. It was quite easy though but I enjoyed finding the solution anyway, thank you!
@@aiman9365 Hahaha 🤣
This is one of the very few ones that only took me about a minute to do.
Yes, I figured this out
Actually there are many puzzles which uses this feedback technique, like a + × -=- and -×+=-
So the key is multiply, in this feed one result to the other, then the result does not depend on true/false (+/-)
"But you do not which door is what type" I think there should be "know" in there somewhere.
Thats to make it harder. First you must complete the sentence, then solve the riddle
We take two doors and push it somewhere else!
the heck?
Just use the warden as a test dummy
Why not pick door A?
Patrick reference?
I would point to the left door and ask: Is the door directly next to it the door for the imprisonment?
If he answers with yes, I'll pick the door at the right, because when he lies, the wrong door is the left one, when he tells the truth, it's the one in the middle so regardless if he tells the truth or not, the door on the right is the right answer. If he replies to my question with no, I'll pick the middle door, because if he sais the truth, it's the way to go and even if he lies and replies with no, I know that the middle door is save, because: he lies and the left door is the wrong one.
So referring back to my question:
If he sais yes, pick the door on the right, if he answers no, pick the one in the middle.
I would point to a random door then ask the warden, "You want to hear the most annoying sound in the world?" then proceed to demonstrate it non stop until he got tired of it and let me go free.
I love how I thought only 1 of them lead to freedom*face slap*
You are not alone on that :)
How about something like "are you answering my current question with a "no"? It would be impossible to answer the question truthfully, so any answer would prove the door isn't safe.
but if the door you pointed to while asking that was safe, what would he answer?
edit: I realized he would probably just say that he doesn't know.
I give him a paradox so if it is freedom he will struggle to answer, but if it was inprisonment, he would answer easily
The better way to phrase the answer is "point at the center door and ask 'is this door to the right of one leading to freedom?'" that way you're still asking a question about the door you're "pointing at", not just cheating by pointing at one door and asking a question about another.
Point at door A and ask "Is 'no' the correct answer to this question?"
If the Warden answers with "yes" or "no" then you must be pointing at the door to imprisonment as there is no truthful answer.
Does it qualifies as a yes/no question though?
If there is no possible answer, it's probably not a binary question.
My key insight while figuring it out was that I saw, that when you point at one door, you cannot choose that door no matter what the answer, because that answer would be random in the case you try to avoid, namely that door leading to imprisonment and you choosing it. Under that constraint it was all really simple to know what to ask and which of the other doors to choose on which answer, because what the question was would only be relevant in the case that you point to a door that leads to freedom, so you expect the answer to be right. Just ask which of the other two doors is safe (and put it in a yes-no form of course).
I know i'm 6 years late, but this doesn't make sense to me, if door B leads to imprisonment, and you ask "does door B lead to freedom" and he randomly says "yes" then you pick door B and you get imprisonment. yes you have a higher chance to get it right but it's not a guarantee, I may not have understood or something but i don't understand how this is guaranteed.
If door B is bad, he can't answer randomly and he would have to say no. If he's answering randomly, that means door A is the bad one, so it doesn't really matter what he says, the other two are good.
Point to door 1 and ask "is the middle door the door to imprisonment?" If the answer is no, and you pointed to the freedom door, then you're safe to walk through the middle door. If the answer is no, and you pointed to the imprisonment door, then you're still safe to walk through the middle door.
If the answer is yes, and you pointed to the freedom door, then you're safe to go through the right door. If the answer is yes, and you pointed to the imprisonment door, you're still safe to go through the right door.
No = use the middle door
Yes = use right door
couldnt you always go to door C after asking the question because its the way to freedom in both cases
Door C does not lead to freedom in the case where A and B both lead to freedom.
I thought in doing that but than I thought it would be against the rules to point to a door and ask about a different door.
Leonardo F. Araujo Exactly, I thought you could only ask a question related to the door you're pointing it.
Nothing in the question suggests it'd be against the rules. It doesn't say 'ask a yes-no question about the door you're pointing to'. It just says to point at a door and ask a yes-no question, and that the truth of the warden's answer depends on the door you're pointing at.
This is a logic puzzle, so take all the instructions at their face value - if something is not logically ruled out by the instructions, then you can do it.
it also may be considered strange, then, that we need to point to a door at all, if we are allowed to ask any y/n question.
Generally great work though from MYD
+ChannelMath
The door you point to determins the validity of the warden's answer. If you didn't point at all, the warden wouldn't be able to answer at all.
To me the solution is not exactly to be smart but to exploit a flaw on the rules the evil warden gave to you. Just like the lawyers do to free bandits here in Brazil.
Mine solution was to ask "If it were a bad door would you answer yes right now?
If its a good door then the answer will be "It depends" since the answer is random
Otherwise if the answer yes or no then this door is bad and you should pick another
Considering that the average warden does not routinely allow prisoners a 66.67% chance (or 100% chance if they're good logicians) of escaping prison, I'd say "evil" is slightly off-base.
This is similar to the most recent ted-Ed riddle, except the ted-Ed one was a much more complicated version with other factors too.
Exactly, I noticed that too. I have a feeling mindyourdecisions was inspired by it, since they came out within weeks of each other.
I spent some hours on the TED-Ed one without figuring it out. But having seen the solution to that, this came easily.
Ape-ocalypse Please provide the link to the TED-Ed video you are referring to. Thanks! :-)
it's called "Can you solve the three gods riddle? - Alex Gendler"
not sure if i can post a link in the youtube comment section
I thought exactly the same!
Can you provide the link to it?
Here’s my solution.
For this method you must never enter the first door, you only question it.
Pointing at the first door, ask this:
“If I asked this door and the middle door an infinite amount of times if this door leads to freedom, would both answers always be yes?”
Scenario 1:
Doom - Freedom - Freedom
If Yes: Enter the middle door
If No: Enter the last door
Scenario 2:
Freedom - Freedom - Doom
Yes is the only possible answer here.
Therefore: Enter the middle door
Scenario 3:
Freedom - Doom - Freedom
No is the only possible answer here.
Therefore: Enter the last door
So no matter what possible door arrangement you’re dealing with…
If you get a Yes,
Freedom is always the middle door guaranteed.
If you get a No,
Freedom is always the last door guaranteed.
Haha I definitely overthought this one. The simpler question in the video does the same thing.
Either way, freedom is still attained and an eternity in hell is avoided. Happy days!
In your outcomes, first row should read "Yes - Door A or B = Freedom" then for the next line "No - Door A or C = Freedom" then the next line down "Yes - B or C is freedom" and then "No - B or C is freedom" - you're getting steps ahead of what you know with how you explain it and it's only after you compare them that you can see that B is freedom in both "Yes" scenarios and C is freedom in both "No" scenarios
How about if you simply point to a door and asked him/her, "Would you walk through this door please ? ". His/her answer will clearly depend on what he/she sees in you. Based on that and depending on what you also see in him/her and your own prevailing sensibilities at the time, you can decide, but I would suggest taking your own sweet time.
It would fit also: point door c and ask does one between a and b bring to freedom?
Doesn’t work, if the warden says yes, you don’t know if it was truthful, or just a randomly selected yes.
If you mean "At least one", then it's a tautology, if you mean "exactly one", then it's the same as asking "is C freedom", none of these work.
when the answer of the imprisonment warden is random You can't figure it out which door leads to freedom.
You actually can. Using the strat in this video, if the warden answers yes, then either the warden is telling the truth and door b is safe, or the warden was speaking randomly and happened to say yes, in which case the unsafe door is a, therefore door b is safe. It’s the same if he says no, either he was telling the truth and door b is in fact the bad door, in which case door c is safe, or he was speaking randomly, which again means that door a is the unsafe one so door c is still safe.
you can take other door and imagine that he is saying the truth in base of what he says to select the door
remember that only 1 door is bad, if he says random is because the door you point is bad, because only if is bad he do random, and therefore the other 2 are good
you know that if he lies is because the other are correct
I figure almost similarly, but would ask instead "Is door B the same type with door A?" whereas "the same type" denotes "leads to freedom".
Not allowed, but other solution: ask "Am I going to pick the right door?" If you've pointed to a good door, the warden answers truthfully, saying "I don't know," and if it is a bad door, he says either "yes" or "no" as per the rules.
when u see the warden do a coin flip to do it randomly u know u picked the wrong door
Unless the warden always flips a coin.
fck i got rekt
Or they don't flip a coin and have a RNG in their brain.
Ok... haven't seen the video yet, i have a solution:
Point Random Door;
Ask "Banana?", if The Warden says either yes or no you'll know that it isn't the right door, if he says something like "What?" you know that door leads to freedom.
lol that i really smart
you can only ask yes or no questions. if you ask banana, you wasted your only question, which means now you have a 33.33% chance of eternal imprisonment
@Ferret man, just because the question is a yes/no question does not mean those are the only answers the warden can give.
Wonderful problem. Didn’t think of it at all.
I guess I solved it in a way which is equivalent, I thought about pointing the door A and asking if the door B is the same as door A. This case work exactly like your solution if the answer is yes in both of the cases you choose the door B and if the answer is No in both of the cases you choose the door C.
I'm proud to have solved it in about 2 minutes. I was expecting a really hard puzzle, but it was fun. I'll try the hard version :)
This one seems easy (especially compared to the Ozo Ulu one). Point to the door in the middle (you're not using that one for sure). Ask "will the door to the right of that lead to freedom"? Assume the answer is truthful because if you pointed to the bad door, you already won. If the answer is "yes", use the right door. If the answer is "no", use the left door.
Um... pretty sure that the Ozo Ulu one is from Ted-Ed
The logic is simple but the interpretation of it is so complicated.
Btw, excellent question...
Inconceivable !
Merely pointing at a door to ask a question about another door makes no sense to me and seems like a cheap loophole against the spirit of the rules.
The actual solution had to be: pointing at any other than the central door, ask "is this door next to the path to freedom?"
Now the question refers to the door you actually point at, and it is the content of the question itself what leads to the rest of the reasoning process.
Good point. I too was a little put off by the pointing to one door and asking about another. Yours is a clever way around it.
idlingdove thank you, I appreciate your comment!
"is this door next to the path to freedom?"
If this is a safe door he will answer yes since there is another safe door.
If this is the imprisonment door and that he is being honest he will also answer yes.
You can't distinguish these two situations with your question
Zygo Petalum if his answer is yes, you pick the central door because you have either been correctly informed or you have been given a random answer, both ways meaning that the central door is safe; on the contrary, if the answer is no, you pick the door at the other end, since that answer might have been truthful, rendering the central door unsafe, or random - either way, the furthest door is safe with a negative reply.
ok sorry i thought you said you had to pick the central door.
I WOULD ASK - *IS THIS AIR U THINK U R BREATHING!?*
That's a good one
That took me WAY longer to work through than I'd thought it would. :(
Let's Go! I said to point to the middle door and ask if the door to the right leads to freedom. If he answers yes, then pick the door to the right. If he answers no, then pick the door to the left. Same logic but easier to visualize.
You should ask: are the two door leading to freedom adjacent? If yes, pick the middle door. If no, pick one of the door on the right of left.
*or left
Which door do you point at?
hahaha.. doesnt matter which door you point at... won't make any difference.. this is the best answer ever
You realise that doesn't work right??? lol
hehehe.. yes i know... just trying to confuse Mr parabola :P
SIMILAR QUESTION :
You are facing two doors after you Die. One leads to heaven the other one to Hell. In front of each door there is an angel and a demon placed randomly. You dont know who is the angel and who is the demon and you can only ask one question to know witch door leads to heaven. What is that question ?
====SOLUTION====
Question : What would the guy in front of the other door says if I ask him wich door leads to heaven ?
Explication :
If you ask the angel that question he will answer you what the demon will say by lying. So you just have to pick the other door.
If you ask the demon this question he should tell you what the angel should tell you by indicating you the real heaven's door. But he's a liar so he'll indicate you the hell's door. So you just have to pick the other door.
I apologize for my bad english I come from France :x
I think I have another valid answer :
"If I asked you wether the other door leads to Hell, would you answer yes ?"
If the other door is leading to hell (therefore we talk to angel) he answers yes. If the other door leads to heaven, and we talk to the demon, then he would answer yes to "Does the other door leads to Hell" (he lies), so he should answer yes to our question, but because he lies (again :D), he says no.
Therefor if the answer is yes, we are talking to the angel and we pick this door, and if the answer is no we are talking to the demon and we have to pick the other door.
This can be done way simpler.
Just ask "Is 1 equal to 1?" and the angel would answer yes, while the demon would answer no.
SmileyMPV Yes your right It would make more sens if the angel and demon are placed randomly in front of the doors I'll correct it
so then you know which one is the angel and which one is the demon, but they are placed randomly, thus you still don't know which door to take.
I point to any door asking if the one to the x side leads to freedom
1) the answer is "yes" : I open that next door.
2) the answer is "no" : I open the (3rd) remaining door
Easy. Poinjt to a door, ask " does this door lead to imprisonment?". If the door does lead to freedom, he's forced to say " i cant answer the question ", then choose that door. If he lies then he'll say "yes/no", then choose one of the other doors. Similar to other games.
Lies he says yes or no RANDOMLY
Point to door b, ask about door a is safe..... says yes (but its randomly) so it means that B is the safe door because door a is death door, and because theres 2 freedom doors so just choose b, its still the same in the video
Point to door a, says no (but its randomly) so it means that door a is deathly door so door c and b is also safe, but it says in the video go to door c, so its still safe.....
What about the warden answers truthfully? Well, watch the video, its really hard to explain it and type it, so.... just check the video again and try to think again.....
How do you know that door A doesn’t lead to freedom
You can't know that, but it's irrelvant because you are not going to pick door A.
These is no need to identify both doors that lead to freedom, just one of then.
You cannot know for certain all the good and bad doors position. You reach that conclusion after some thinking, then the only possible way is to get information no matter which door is responding to your question, and you'll get info about only one door.
I might have been on the right track. I thought about pointing to door A and asking if both door B and C lead to freedom. If he said yes he wouldn't be being truthful, one of them would have to be bad for him to tell the truth, B and C are good to go. If he said no then go through door A. I shouldn't have looked at the answer, I would have got it in a month or so.
You could also ask a question that has no good answer, like “If I were to tell you that I am lying to you, would I be lying?” If it was the wrong door, he would answer yes or no. If it was one of the safe ones, he would be forced to give a different answer.