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| 60933 |
A Logic Problem to Solve
Hi friends,
Below is a logic question anyone interested should read it first and can ask me for answer if she wants:
A prisoner is kept in a room with two jailers.The room has two doors, one to freedoom, and the other to a certain death. The prisoner knows this, but he does not know which door is which. He also knows that one of his jailers always tells the truth, and the other always tells lies, but he does not know which jailer is the truth-teller and which is the liar. He is allowed to ask just ONE question of one of the jailers : he may choose which jailer to ask , and he may decide what question to ask.(Both jailers know which door is which, and each knows the other's lying or truthful disposition.) What single question can the prisoner ask in order to find out for certain which door leads to freedoom?
If you have suggestions or want to know the real answer, simply contact me.
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Language pair: English; All
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| 61089 |
Re:A Logic Problem to Solve
whats the answer to the logic question?!? :D
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Language pair: English; All
This is a reply to message # 60933
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| 61246 |
Re:A Logic Problem to Solve
Hi. I have bene trying to work out this riddle for a while and cannot work out the question. All i came up with was that the prizoner could be one of the jailers therefor he knows who is and isn't the lier so he will not have to ask any question? Anyway please get back to me i would love to know the question!
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Language pair: English; All
This is a reply to message # 60933
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| 61574 |
Re:A Logic Problem to Solve
so the answer is (I hope I'm not spoiling this to anyone), I think, that the prisoner should ask one of the jailers this question: if I would ask your friend (or other jailer)which door are 'freedom' what would he tell me? ...
here is another one:
there are 2 isolated rooms. one has 3 lights (luminaires)and in the other are 3 switches. there is one persone in the room with switches, and for every switch there is one light but the man doesn't know what light is for what switch.The persone should guess what light is for what switch. So the persone can turn the switches on and off and can go to the room with lights but than must stay there (so, only one walk is alowed).
How can persone guess this?
I hope I wrote this so it can be understood :)
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Language pair: English; All
This is a reply to message # 60933
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| 61650 |
Re:Re:A Logic Problem to Solve
The person should turn in one switch and leave it on for a long time. Then turn that switch off and turn on a second switch then walk quickly to the room. The bulb that is on belongs to the second switch. The person should touch the other two bulbs and the bulb that is hot belongs to the first switch.
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Language pair: English; All
This is a reply to message # 61574
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| 62130 |
Re:A Logic Problem to Solve
Warning: the following answer requires a very good understanding of the English subjunctive tense and a good sense of logic.
Let's name the doors 1 and 2.
You should ask either jailer the following question and that will give you sufficient information to decide:
If I _were_ to ask you "Does door 1 lead to freedom" would you answer "yes"?
(Call this subjunctive sentence "the complicated question" to be distinguished from "the simple" question," which is simply "Does door 1 lead to freedom?"
There are two possibilities: either the jailer you are asking is a liar or a truth-teller.
CASE 1:
Suppose the jailer is a truth-teller: then no problemo - if the jailer says "yes", then door 1 will lead to freedom, whereas, if the jailer says "no" then door 2 will lead to freedom. Either way if the jailer is truth-treller you will have sufficient information.
CASE 2: Suppose the jailer is a liar: then the jailer would also answer "yes" if door 1 leads to freedom and "no" if door 2 leads to freedom - exactly the same answer that the truth-teller would give. You will still have sufficient information to decide which door to take. I know this sounds counter-intuitive, but consider the only two possibilities Case 2a and case 2b:
Case 2a: Door 1 does lead to freedom. In this case if you asked the lying jailer the _simple_ question: "Does door 1 lead to freedom?", the jailer would have to lie and say "no". But if you ask him the complicated subjunctive question, in order to lie, he must answer "yes" _otherwise he would be telling the truth!_ Were you to ask the lying jailer _how_ he would answer your simple question he would lie and say "yes".
Case 2b: Door 2 leads to freedom. In this case, in order to lie, the lying jailer must answer "no" to the complicated question; he would answer "yes" to the simple question. Hence again, in this case the lying jailer would give the same answer as the the truth-telling jailer and you would have enough information to reach freedom.
So to conclude: if either jailer answers "yes" then door 1 leads to freedom, and if either answers "no" then door 2 leads to freedom.
QED
(By the way, I used to be a logic prof.)
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Language pair: English; All
This is a reply to message # 60933
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| 62137 |
Re:A Logic Problem to Solve
Warning: the following answer requires a very good understanding of the English subjunctive tense and a good sense of logic.
Let's name the doors 1 and 2.
You should ask either jailer the following question and that will give you sufficient information to decide:
If I _were_ to ask you "Does door 1 lead to freedom" would you answer "yes"?
(Call this subjunctive sentence "the complicated question" to be distinguished from "the simple" question," which is simply "Does door 1 lead to freedom?"
There are two possibilities: either the jailer you are asking is a liar or a truth-teller.
CASE 1:
Suppose the jailer is a truth-teller: then no problemo - if the jailer says "yes", then door 1 will lead to freedom, whereas, if the jailer says "no" then door 2 will lead to freedom. Either way if the jailer is truth-treller you will have sufficient information.
CASE 2: Suppose the jailer is a liar: then the jailer would also answer "yes" if door 1 leads to freedom and "no" if door 2 leads to freedom - exactly the same answer that the truth-teller would give. You will still have sufficient information to decide which door to take. I know this sounds counter-intuitive, but consider the only two possibilities Case 2a and case 2b:
Case 2a: Door 1 does lead to freedom. In this case if you asked the lying jailer the _simple_ question: "Does door 1 lead to freedom?", the jailer would have to lie and say "no". But if you ask him the complicated subjunctive question, in order to lie, he must answer "yes" _otherwise he would be telling the truth!_ Were you to ask the lying jailer _how_ he would answer your simple question he would lie and say "yes".
Case 2b: Door 2 leads to freedom. In this case, in order to lie, the lying jailer must answer "no" to the complicated question; he would answer "yes" to the simple question. Hence again, in this case the lying jailer would give the same answer as the the truth-telling jailer and you would have enough information to reach freedom.
So to conclude: if either jailer answers "yes" then door 1 leads to freedom, and if either answers "no" then door 2 leads to freedom.
QED
(By the way, I used to be a logic prof.)
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Language pair: English; All
This is a reply to message # 60933
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