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Who stole the candy bar? (Posted on 2005-02-03) Difficulty: 3 of 5

During lunch hour at school, a group of five boys from Miss Jones' home room visited a nearby lunch wagon. One of the five boys took a candy bar without paying for it. When the boys were questioned by the school principal, they made the following statements in respective order:

1. Rex: "Neither Earl nor I did it."

2. Jack: "It was Rex or Abe."

3. Abe: "Both Rex and Jack are liars."

4. Dan: "Abe's statement is not true; one of them is lying and the other is speaking the truth."

5. Earl: "What Dan said is wrong."

When Miss Jones was consulted, she said, "Three of these boys are knights, but two are liars." Assuming that Miss Jones is correct, can you determine who took the candy bar?

See The Solution Submitted by Jane Doe    
Rating: 3.0000 (5 votes)

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Solution | Comment 5 of 36 |
Assume Rex is a knight. Then Abe must be lying. If Jack is also a liar, then we have two liars, so Dan and Earl must both be telling the truth, which is a contradiction. Therefore, Jack must be a knight. This makes Dan's statement a lie and Earl's the truth.

Knights: Rex, Jack and Earl
Liars: Abe and Dan

Jack says the person who took the candy bar was either Rex or Abe, but Rex says he did not do it, therefore it must have been Abe.

  Posted by yocko on 2005-02-05 19:54:33
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