Thread: PR 4 # 23
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Old 2006-06-23, 14:37   #4
R.D. Silverman
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Nov 2003

746010 Posts

Originally Posted by Chris Card

maybe I've gone wrong, but I can see two answers:
A, B and D lying, C and E truthful
A, C and E lying, B and D truthful
Impossible. If A is lying, then his statement is false.
But if his statement is false then D is telling the truth. But your
case 1 says D is lying.

In case 2 If A is lying, then C must be telling the truth.

I can't find any combination that doesn't lead to a contradiction.

Suppose A is telling the truth. Therefore C & D are lying.
But if C is lying, then D is telling the truth --> contradiction

Suppose A is lying. Then C & D are telling the truth. But if C is telling
the truth then D is lying, contradicting A.

A can be neither lying nor telling the truth.

Something doesn't add up.
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