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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