OpenEuphoria

Re: Logic challenge (a REALLY tough problem)

• Posted by Dan Moyer <DANIELMOYER at prodigy.net> Feb 20, 2002
• 405 views

oops.  miscopied a step in my logic, but otherwise I think all conclusions
are correct:
(and now that I look at Derek's, I think they are the same logic, just
different format?)

Dan

----- Original Message ----- >
> This one IS tough (for me):
>
> I work it out *negatively*:
>
> 1.  if A is NOT a fighter, then:
>      statement one means older fighter must be  B
>      statement three means younger fighter must be C
>      statement one also means   A is taller than C   <===========  ERROR
    NO, MEANS A IS TALLER THAN B
>      statement three also means A is shorter than B  <===========  ERROR
  NO, MEANS A IS SHORTER THAN C
>      so heights are, taller to shorter:   C  A  B  <====   STILL TRUE
>      statement two means the shorter fighter, B, is the YOUNGER of the
> fighters,
>      which contradicts the first conclusion above, which means the
> assumption
>         that A is not a fighter is WRONG;
>
> 2.  if B is NOT  a fighter, then:
>      statement one means A is older fighter
>      statement two means C is shorter fighter
>      since A is older, three means A is also shorter than C
>      but that contradicts the 2nd conclusion above, which means that the
> assumption
>           that B is not a fighter is WRONG;
>
> 3.  since A cannot NOT be a fighter, then A must BE a fighter; and,
>      since B cannot NOT be a fighter, then B must BE a fighter;
>      so if A and B must be fighters, and there are only 2 fighters,
>      then C must NOT be a fighter.
>
> Whew!!   I hope someone else found a better way!  Hard enough to develop
the
> logic, harder to go back 3rd time and proof it.
>
> Dan Moyer
>
>
> ----- Original Message -----
> From: <petelomax at blueyonder.co.uk>
> To: "EUforum" <EUforum at topica.com>
> Sent: Tuesday, February 19, 2002 3:10 PM
> Subject: Re: Logic challenge (a REALLY tough problem)
>
>
> I believe this to be the mother of all logic problems.
> I have not seen a more difficult one.
> (You only get half a point for writing a program to solve it!)
>
> Pete
>
> Two of Anthony, Bernard, and Charles are fighting each other.
>
> 1. The shorter of Anthony and Bernard is the older of the
>    two fighters.
>
> 2. The younger of Bernard and Charles is the shorter of the
>    two fighters.
>
> 3. The taller of Anthony and Charles is the younger of the
>    two fighters.
>
> Who is not fighting?
>
> >