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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: 2.3333 (3 votes)

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Solution Puzzle Solution Comment 25 of 25 |
(In reply to answer by K Sengupta)

Since precisely three of these boys are knights, but two are
liars, we examine each of the five cases wherein each of the
five individuals in turn are guilty, and verify whether
the respective number of liars and knights in each of those
five situations conform to the given conditions.

These five situations are now examined in terms of the
following table:

 

Situation            Conclusion                  Remarks

Rex is Guilty    Abe, Rex and Earl         Contradiction
                     are liars,and Jack
                     and Dan are knights                                         
               

    
Jack is Guilty   Jack, Abe and Earl        Contradiction
                      are liars and Rex
                     and Dan are knights
                                                  
               
Dan is Guilty    Jack, Abe and Dan       Contradiction
                      are liars,and Rex
                     and Dan are knights
                                           
               
Earl is Guilty   Rex, Jack and Dan         Contradiction
                     are liars,and Abe      
                     and Earl are  knights                                                        
               

Abe is Guilty    Abe and Dan are         Conform to the
                     liars,and Rex, Jack        given conditions 
                     and  Earl are
                     knights

                                                   
                 

Consequently, Abe took the candy bar.

Edited on June 11, 2008, 4:45 pm
  Posted by K Sengupta on 2008-06-10 23:46:30

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