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Four suspects of a crime made the following statements to the police:
Andy: Carl did it
Bob: I did not do it.
Carl: Dave did it.
Dave: Carl lied when he said I did it.
Given that exactly one of them "did it" and that exactly one told the truth. Who did it?
If Bob told the truth, that means he did it. Therefore, Dave would have also told the truth about Carl lying that he did it. We can have two truth speakers. Therefore, Bob lied--and he did it. Dave told the truth.
Another way: If Dave had lied, both Bob and Carl were telling the truth, so Dave could not have lied. Because Dave told the truth Bob must have lied--and did it. :)
also Andy could have done it, Dave speaking the truth
In short Bob did it & the 4th person in list told the truth.
Thread resolved!!!
Then both Dave and Bob told the truth. Not allowed. See my post: If Dave told the truth, then Bob must have lied--and did it. (My first way is a bit jumbled, just look at the "another way:" bit).Quote:
Originally posted by kedaman
also Andy could have done it, Dave speaking the truth
you're right, didn't think straight there..