Re: Puzzle

["GUEST2: RSE_SYSENG" <GUEST2@holonic.gse.rmit.edu.au>]

> Date:          Wed, 2 Jul 1997 02:25:50 -0500 (CDT)
> Reply-to:      vnsa-l@csd.uwm.edu
> From:          Dang Hung Thang <thang@mathematik.uni-Bremen.de>
> To:            Multiple recipients of list <vnsa-l@csd.uwm.edu>
> Subject:       Puzzle

> Cha`o ca'c ba'c quan ta^m to+'i mu.c Gia?i tri' Toa'n ho.c
> Do Ngoc Minh gave a nice answer to the Politican Puzzle. Here is
> another puzzle which is simple but not very easy.
>               The twin brothers
> There are twin brothers one of the two is named An. One lies and one tells
> the truth. How can you discover which brother is An by asking them ONE
> THREE-WORD QUESTION ?
> Cheers
> Thang

An answer possible is 
                  Does An lie?

The one who answer No is An.

Let's see the table

           Truth   Lie                  Truth   Lie 
           An                                       An
----------------------------------------------------------
Reply   N       Y                     Y       N

Either way, An always say No.

Ba`i na`y hay tha^.t.  Anh Tha('ng ra the^m va`i ba`i kha'c -di.

Tuan 
Melbourne, Australia