Brain Teasers
The 3 Prophets
Once upon a time there were 3 prophets:
One always tells the truth
One always lies
And one sometimes lies and sometimes tells the truth.
In order to find out who is who, you ask the three if the middle one is the truthteller, liar or "sometimes". The first says "the middle one always lies". The middle one said "I sometimes lie and sometimes tell the truth". The third one says "he always tells the truth". You know for a fact that this time the one that sometimes lies and sometimes tells the truth is lying. Which one of them is which?
One always tells the truth
One always lies
And one sometimes lies and sometimes tells the truth.
In order to find out who is who, you ask the three if the middle one is the truthteller, liar or "sometimes". The first says "the middle one always lies". The middle one said "I sometimes lie and sometimes tell the truth". The third one says "he always tells the truth". You know for a fact that this time the one that sometimes lies and sometimes tells the truth is lying. Which one of them is which?
Answer
The middle one said that he is the "sometimes" prophet. If this were true, he could only be the truth teller. since we know that the "sometimes" is lying - this situation is impossible, since if he were the truthteller he would have said that he were the truthteller. From this we conclude that the middle one is the lying prophet, which means that whoever said that he was the lying prophet is the truthteller. Since the first prophet said that, he is the truthteller, and the third is the "sometimes".Hide Answer Show Answer
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Comments
This could be hard if you don't how logical statements work.
I know. My friend told it to me when I was 12 and it took me a while...
I got this one, which surprised me cuz I didn't know I knew how to do these....
you'll get it if you think a little while
It would make more sense to say the Middle one is lying when telling the brain teaser because the person has not yet identified who's telling the truth and who's not. Good one though
i absolutely disagree! if you said that one of them sometimes tells the truth and sometimes lies, there is no way of knowing when he'll say what! to my opinion, this teaser is wrong!
Which is wht the teaser says: "You know for a fact that this time the one that sometimes lies and sometimes tells the truth is lying"
Actually, you don't need the statement that the "sometimes" prophet is lying now - you can figure it out from the rest of the info
(though it does make the problem easier). If the middle prophet were telling the truth, he would have to be the "sometimes" prophet, and
the other two would both be lying - which contradicts the statement that there was a truth teller.
So he has to be lying, hence he has to be the liar. So the first prophet must be telling the truth,
and the third prophet is currently lying. But since we've already identified the second prophet as the liar, the third
prophet must be the "sometimes" prophet who is currently lying.
(though it does make the problem easier). If the middle prophet were telling the truth, he would have to be the "sometimes" prophet, and
the other two would both be lying - which contradicts the statement that there was a truth teller.
So he has to be lying, hence he has to be the liar. So the first prophet must be telling the truth,
and the third prophet is currently lying. But since we've already identified the second prophet as the liar, the third
prophet must be the "sometimes" prophet who is currently lying.
Yes dewey. That's what led me to error on this one. Since the third prophet must be lying, I rushed in and concluded he was the liar. Actually he must be lying on this occasion but according to the other statements he doesn't always. Nice teaser, nearly got it!
This one plagued me for a whole thirty seconds before I hit the answer button!
No lie. total truth, sometimes?
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