OpenEuphoria

Re: Logic challenge (a REALLY tough problem)

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

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
     statement three also means A is shorter than B
     so heights are, taller to shorter:   C  A  B
     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?