Look at the 5 statements below (in the column at right is the name of the person who made it):

      | A |           I tell the truth                   |   BOB   |
      | B |       JIM doesn´t tell the truth             |   TOM   |
      | C |          KEV tells the truth                 |   JIM   |
      | D |          BOB tells the truth                 |   KEV   |
      | E |            TOM tells lies                    |   LEN   |

Only one of the 5 people is telling the truth. Remove the name of the truth-teller and place the names of the remaining 4 in the same order in the next board, ie, if JIM is telling the truth, JIM will be removed and in the next board you will place the names BOB (in line F), TOM (in line G), KEV (in line H) and LEN (in line I), in the column at right.

      | F |    KEV told the truth in the grid above       |         |
      | G |    I was in position B in the grid above      |         |
      | H | The person in position F is telling the truth |         |
      | I |              I am not KEV                     |         |

Only 1 of the 4 people is telling the truth. Remove the truth-teller from the line-up and proceed as above with the remaining 3 names.

      | J |   The person in position K is telling a lie   |         |
      | K |        I was not in position G above          |         |
      | L | The person in position J is telling a lie     |         |

Only 1 of the 3 people is telling the truth. Remove the truth-teller from the line-up and proceed as above with the 2 remaining names.

      | M |   The person in position N is telling a lie   |         |
      | N |                I am KEV                       |         |

Only 1 of the 2 people is telling the truth. Remove the truth-teller from the line-up.

Who is the consistent liar ?

JIM is the consistent liar.  Let's do the analysis.

Let's start in the first part.  If Bob were telling the truth, then Kev would also be telling the truth (because he says that Bob tells the truth) and therefore both are lying.  If Kev is lying, then Jim, who said that Kev tells the truth, is also lying.  Tom, who says that Jim doesn't tell the truth, IS telling the truth.  Supporting this, we have Len's lie (that Tom doesn't tell the truth).  Therefore, on the first grid, the person telling the truth is TOM.

In the second grid, we have Bob (F), Jim (G), Kev(H) and Len(I) left.  First, we see that Len is not Kev, and therefore he is telling the truth.  It's not even necessary to go on, but let's explain anyways.  Since Bob is saying that Kev was telling the truth last round (which he wasn't), then Bob is lying.  This instantly eliminates Kev, who says that Bob is telling the truth.  Jim wasn't on the B grid on the first round, so he's a liar too.  Therefore, on the second grid, the person telling the truth is LEN.

In the third grid, we have only Bob (J), Jim (K) and Kev (L) left.  Since Jim WAS in position G on the last grid, he is lying.  This instantly grants Bob the truth, and also makes sure that Kev is lying.  So, for the third grid, the person telling the truth is BOB.

This leaves a very easy choice between Jim (M) and Kev (N).  Since, well, Kev is Kev, then KEV is telling the truth.

This would make JIM the consistent liar.

Posted by Alexis on 2005-11-02 16:13:08