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Legally Blonde (Posted on 2016-12-19) Difficulty: 1 of 5
You meet three blonde women, A, B, and C. Each of them is either a knight or a liar. Exactly one of them is Elle Woods.

A:I am Elle Woods.
B:I am Elle Woods.
C:At least two of us are liars.

What are A, B, and C, and who is Elle Woods?

No Solution Yet Submitted by Math Man    
Rating: 3.0000 (2 votes)

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Solution another way | Comment 3 of 8 |
On inspection we see the possibility that A and B are liars, C is telling the truth and C is the real Elle Woods. Also it's the only possibility that allows itself to be unique as any logic leading to either A or B being the real Elle Woods would also apply to the other in that pair.

But to actually eliminate that possibility logically, just assume that A is the real Elle Woods. Then B would be lying and you'd have the paradox that if C were telling the truth she'd be lying, but if she were lying, she'd have to be telling the truth.

So indeed C is the real Elle Woods and A and B are lying and C is telling the truth, as the only knight.

  Posted by Charlie on 2016-12-19 10:31:34
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