Thread: PR 4 # 23 View Single Post
2006-09-20, 22:23   #8
Maybeso

Aug 2002
Portland, OR USA

2·137 Posts

While I was catching up on these puzzles, I noticed the posts for this one are all about interpretation, with no solutions!
Quote:
 Originally Posted by Chris Card If A is lying then it's not true that C and D are lying, which means C or D or both are telling the truth.
Quote:
 Originally Posted by R.D. Silverman ...the negation of "C and D are lying" is C *or* D is telling the truth and not "C *and* D are telling the truth".
If the puzzle is evaluated in this way then:

A is telling the truth means that C and D are lying, which means that
B or D is telling the truth AND [COLOR="Yellow"]C or [COLOR="Lime"]E[/COLOR] is telling the truth[/COLOR], which means that
A and E are lying OR C and E are lying AND [COLOR="Yellow"]B and D are lying[/COLOR] OR [COLOR="Lime"]A and B are lying[/COLOR].

A is telling the truth implies that either A is lying or D is both telling the truth and lying. So A is lying.

Evaluating the other suspects statements in a similar way gives two possible solutions:
If B and D are telling the truth, then A, C, and E are lying.

If C and E are telling the truth, then A, B, and D are lying.