Brain Teasers
Truths and Lies
There are three persons in a room.
One of them always tells the truth, but the others are "alternate liars": they tell the truth then lie, then truth, etc, but you do not know if they will start by telling the truth or a lie...
You can ask three questions that MUST be answered by Yes or No.
Find the truth teller.
One of them always tells the truth, but the others are "alternate liars": they tell the truth then lie, then truth, etc, but you do not know if they will start by telling the truth or a lie...
You can ask three questions that MUST be answered by Yes or No.
Find the truth teller.
Hint
Ask the questions to one person only.Answer
Q1. Mr. A, are you a truth teller?- Yes
or
- No.
Q2. Mr. A, are you a truth teller?
- Yes
or
- No.
Q1: Q2:
Yes Yes: A is the truth teller.
Yes No : A is an alternate liar, next answer is a lie.
Q3: Mr. A, is B the truth teller?
- Yes: C is the truth teller.
- No: B is the truth teller.
No Yes: A is an alternate liar, next answer is true.
Q3: Mr. A, is B the truth teller?
- Yes: B is the truth teller.
- No: C is the truth teller.
No No : Impossible.
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