3 Guards, 2 Doors?!
Question: You are stuck in a castle room with 2 doors.
One door leads to freedom, while the other to death.
There are 3 guards in the room:
- The Honest Guard: Always Tells the Truth
- The Lying Guard: Always lies
- The Floating Guard: Sometimes lies, Sometimes tells the truth, however he wishes at the moment.
You have 2 Yes/No questions you can ask. (You can ask either one guard 2 questions, or ask 2 guards a question each, as you wish).
After you ask you must enter one of the doors.
What 2 questions and which guard(s) do you ask?
Note: Asking a question which the guard does not know the answer to (Such as: 'Am i gonna make it outta here') will result in a shrug from the guard with no answer.
(This is only in cases where the guard really does not know the answer, he is not allowed to 'lie' and shrug off the question if he knows the answer)
Answers: You are stuck in a castle room with 2 doors.
One door leads to freedom, while the other to death.
There are 3 guards in the room:
- The Honest Guard: Always Tells the Truth
- The Lying Guard: Always lies
- The Floating Guard: Sometimes lies, Sometimes tells the truth, however he wishes at the moment.
You have 2 Yes/No questions you can ask. (You can ask either one guard 2 questions, or ask 2 guards a question each, as you wish).
After you ask you must enter one of the doors.
What 2 questions and which guard(s) do you ask?
Note: Asking a question which the guard does not know the answer to (Such as: 'Am i gonna make it outta here') will result in a shrug from the guard with no answer.
(This is only in cases where the guard really does not know the answer, he is not allowed to 'lie' and shrug off the question if he knows the answer)
Call the guards A, B & C - it doesn't matter which is which.
Ask guard A which door B would tell me is the right one.
He will either answer or shrug - if he shrugs then he must be either the truthful or the false guard, because B is unreliable. If I get any positive answer then I know B is reliable (either truthful or false).
If I know that B is unreliable, ask A which door C would tell me is the right one & go through the other one.
If I know that B is reliable, ask B which door is the one most likely to be identified as good by A & C & go through the other one.
I have never been able to figure this one out!
Ask the floating guard is this the door to death?
Ask the lying guard is he telling the truth?
Go to the door that isn't death based on their answers.
ask the floating guard if the door to death is the left one, and ask the honest guard if he is telling the truth.
Ask any guard 'If I ask the other guards if that's the door to freedom will they say yes?'
Depending on the answer of that guard I'd either go through a door or ask the other guard the same question.
Explaination.
If it is the door to freedom the lying guard will say no for the truth guy or don't know for the switchy guy. If it's no I'd go through a live another day.
The truth telling guard will also say no for the lying guard and don't know for the switchy guard. And again I'd go through to live another day.
The switchy guard, however would be the difficult one - but as you've said they can't say they don't know unless it's the truth - he would be the only guard to give me either two yes's, two no's or a yes and a no. At that point I would ask the other guard the same question and hightail it out of there.
Can I have 10 pts please? :-)
Kill the lying guard and the floating gaurd. Then ask the truthful gaurd, "Do you want to live?" Then ask him which way is out. >:)
but you didn't say i can't identify the guards, so i'll just ask the honest guard which door leads to freedom.
if, however, i cannot identify them, then i will ask the 1st guard "what will the other 2 guards say is the door that leads to freedom?"
if his reply contains "i don't know about the other one, but this one will say this way" then he is NOT a floater because the guard he couldn't predict is the floater. then ignore his reply on the floater and go the way opposite of what he said "the other guard will point to"
if his reply doesn't contain the above statement, then he is a floater and you should ask another guard "what would the 3rd guard (not the floater) say is the door that leads to freedom?" and go the opposite door
the trick to this question is to identify the floater.
as long as you know who the floater is, then it will be the same as the '2 guard 2 door' scenario where you go the opposite after asking "which door will the other guard say leads to freedom?" cause 1 truth x 1 lie = 1 lie