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There are two identical twin brothers.

  • The first one is honest, but he lies in his schizophrenic situations.
  • The second one is well-known liar, but he tells the truth when he gets one of his pathologic seizures .

What kind of yes-no questions should you ask anyone of them to detect whether he is in his normal or in his irregular state?

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    $\begingroup$ There is a simpler way to determine if they tell the truth. $\endgroup$ – KSmarts Feb 17 '15 at 22:25
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do you always speak the truth when you are crazy?

"yes" indicates that they are currently crazy


I just realised that the opposite also works and might be simpler

do you lie on purpose?

"yes" indicates that they are currently crazy

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  • $\begingroup$ there is a simpler and shorter question :D $\endgroup$ – Abr001am Feb 17 '15 at 21:56
  • $\begingroup$ I edited it, it's the same question but simpler. dunno how to make it more simple. $\endgroup$ – user3453281 Feb 17 '15 at 22:21
  • $\begingroup$ you can ... "are you in your pathologic situation ?" $\endgroup$ – Abr001am Feb 17 '15 at 22:23
  • $\begingroup$ but this answer is accepted thu $\endgroup$ – Abr001am Feb 17 '15 at 22:23
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    $\begingroup$ @Abidare001 "are you in your pathological situation" would always be answered no by the honest twin and yes by the liar. It's a useful question, but not what is asked for here. $\endgroup$ – Callidus Feb 19 '15 at 1:36

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