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Which person is telling the truth?

The broken windowWho is the murderer of Mr. Morgan?Another village of liars and truth-tellersThirteen people telling truths or liesTelling the truthWho committed the crime?Telling the truth or lying?Liars, truth-tellers and jokers

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4

$begingroup$

A person was killed. There are 4 suspects.

A says C is the killer.
B says C is the killer.
C says that B is lying.
D says that it wasn't him.

There is only one person telling the truth. Who is this person, and why?

logical-deduction

share|improve this question

edited 9 hours ago

Rewan Demontay

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• 
  
  
  

  
  

  
  
  
  
  
  

  
  $begingroup$
  Are you sure this isn't supposed to be [lateral-thinking] rather than [logical-deduction]? Because there's another solution that I think fits more under the former tag than the latter, and I suspect that's what you're going for.
  $endgroup$
  – Deusovi♦
  9 hours ago
  
  
  

  
  
  
  

add a comment
 | 

4

$begingroup$

A person was killed. There are 4 suspects.

A says C is the killer.
B says C is the killer.
C says that B is lying.
D says that it wasn't him.

There is only one person telling the truth. Who is this person, and why?

logical-deduction

share|improve this question

edited 9 hours ago

Rewan Demontay

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asked 10 hours ago

user63167user63167

2111 bronze badge

New contributor

user63167 is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
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$endgroup$

• 
  
  
  

  
  

  
  
  
  
  
  

  
  $begingroup$
  Are you sure this isn't supposed to be [lateral-thinking] rather than [logical-deduction]? Because there's another solution that I think fits more under the former tag than the latter, and I suspect that's what you're going for.
  $endgroup$
  – Deusovi♦
  9 hours ago
  
  
  

  
  
  
  

add a comment
 | 

$begingroup$

A person was killed. There are 4 suspects.

A says C is the killer.
B says C is the killer.
C says that B is lying.
D says that it wasn't him.

There is only one person telling the truth. Who is this person, and why?

logical-deduction

share|improve this question

edited 9 hours ago

Rewan Demontay

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asked 10 hours ago

user63167user63167

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user63167 is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
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$endgroup$

share|improve this question

edited 9 hours ago

Rewan Demontay

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asked 10 hours ago

user63167user63167

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share|improve this question

edited 9 hours ago

Rewan Demontay

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user63167user63167

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edited 9 hours ago

Rewan Demontay

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edited 9 hours ago

Rewan Demontay

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asked 10 hours ago

user63167user63167

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3 Answers
3

active

oldest

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6

$begingroup$

Who tells the truth is:

C

because

otherwise there would be contradictions in AC, BC and BD pairs in terms of truth telling

share|improve this answer

edited 8 hours ago

tom

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answered 9 hours ago

JohnMollisJohnMollis

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$endgroup$

• 
  
  
  

  
  

  
  
  
  
  
  

  
  $begingroup$
  I edited to hide your reasoning - nice answer - no change to the wording or anything, just the formatting.
  $endgroup$
  – tom
  8 hours ago
  

  
  
  
  

add a comment
 | 

4

$begingroup$

The person telling the truth is:

C

Because:

A and B cannot both tell the truth, so they are both lying.
B and C cannot both be lying, so C is telling the truth

And consequently, the kller is:

D, because he is lying.

share|improve this answer

answered 9 hours ago

WhatsUpWhatsUp

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$endgroup$

add a comment
 | 

2

$begingroup$

I think the answer is

C.

because

If C is lying, then B must be telling the truth. However, if B is telling the truth then A must also be telling the truth. This is a contradiction, so C must be telling the truth.

share|improve this answer

edited 8 hours ago

tom

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answered 9 hours ago

HeavpootHeavpoot

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Heavpoot is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.

$endgroup$

• 
  
  
  

  
  

  
  
  
  
  
  

  
  $begingroup$
  Welcome to Puzzling SE. Note that I put some formatting into your answer so that the answer would not be obvious. You did a nice job of hiding your explanation though. I had to put some words in to make the formatting work.
  $endgroup$
  – tom
  8 hours ago
  

  
  
  
  

add a comment
 | 

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6

$begingroup$

Who tells the truth is:

C

because

otherwise there would be contradictions in AC, BC and BD pairs in terms of truth telling

share|improve this answer

edited 8 hours ago

tom

2,14811 gold badge77 silver badges3030 bronze badges

answered 9 hours ago

JohnMollisJohnMollis

11211 silver badge77 bronze badges

$endgroup$

• 
  
  
  

  
  

  
  
  
  
  
  

  
  $begingroup$
  I edited to hide your reasoning - nice answer - no change to the wording or anything, just the formatting.
  $endgroup$
  – tom
  8 hours ago
  

  
  
  
  

add a comment
 | 

6

$begingroup$

Who tells the truth is:

C

because

otherwise there would be contradictions in AC, BC and BD pairs in terms of truth telling

share|improve this answer

edited 8 hours ago

tom

2,14811 gold badge77 silver badges3030 bronze badges

answered 9 hours ago

JohnMollisJohnMollis

11211 silver badge77 bronze badges

$endgroup$

• 
  
  
  

  
  

  
  
  
  
  
  

  
  $begingroup$
  I edited to hide your reasoning - nice answer - no change to the wording or anything, just the formatting.
  $endgroup$
  – tom
  8 hours ago
  

  
  
  
  

add a comment
 | 

$begingroup$

Who tells the truth is:

C

because

otherwise there would be contradictions in AC, BC and BD pairs in terms of truth telling

share|improve this answer

edited 8 hours ago

tom

2,14811 gold badge77 silver badges3030 bronze badges

answered 9 hours ago

JohnMollisJohnMollis

11211 silver badge77 bronze badges

$endgroup$

share|improve this answer

edited 8 hours ago

tom

2,14811 gold badge77 silver badges3030 bronze badges

answered 9 hours ago

JohnMollisJohnMollis

11211 silver badge77 bronze badges

edited 8 hours ago

tom

2,14811 gold badge77 silver badges3030 bronze badges

edited 8 hours ago

tom

2,14811 gold badge77 silver badges3030 bronze badges

answered 9 hours ago

JohnMollisJohnMollis

11211 silver badge77 bronze badges

answered 9 hours ago

JohnMollisJohnMollis

11211 silver badge77 bronze badges

4

$begingroup$

The person telling the truth is:

C

Because:

A and B cannot both tell the truth, so they are both lying.
B and C cannot both be lying, so C is telling the truth

And consequently, the kller is:

D, because he is lying.

share|improve this answer

answered 9 hours ago

WhatsUpWhatsUp

28366 bronze badges

$endgroup$

add a comment
 | 

4

$begingroup$

The person telling the truth is:

C

Because:

A and B cannot both tell the truth, so they are both lying.
B and C cannot both be lying, so C is telling the truth

And consequently, the kller is:

D, because he is lying.

share|improve this answer

answered 9 hours ago

WhatsUpWhatsUp

28366 bronze badges

$endgroup$

add a comment
 | 

$begingroup$

The person telling the truth is:

C

Because:

A and B cannot both tell the truth, so they are both lying.
B and C cannot both be lying, so C is telling the truth

And consequently, the kller is:

D, because he is lying.

share|improve this answer

answered 9 hours ago

WhatsUpWhatsUp

28366 bronze badges

$endgroup$

share|improve this answer

answered 9 hours ago

WhatsUpWhatsUp

28366 bronze badges

answered 9 hours ago

WhatsUpWhatsUp

28366 bronze badges

answered 9 hours ago

WhatsUpWhatsUp

28366 bronze badges

2

$begingroup$

I think the answer is

C.

because

If C is lying, then B must be telling the truth. However, if B is telling the truth then A must also be telling the truth. This is a contradiction, so C must be telling the truth.

share|improve this answer

edited 8 hours ago

tom

2,14811 gold badge77 silver badges3030 bronze badges

answered 9 hours ago

HeavpootHeavpoot

2122 bronze badges

New contributor

Heavpoot is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.

$endgroup$

• 
  
  
  

  
  

  
  
  
  
  
  

  
  $begingroup$
  Welcome to Puzzling SE. Note that I put some formatting into your answer so that the answer would not be obvious. You did a nice job of hiding your explanation though. I had to put some words in to make the formatting work.
  $endgroup$
  – tom
  8 hours ago
  

  
  
  
  

add a comment
 | 

2

$begingroup$

I think the answer is

C.

because

If C is lying, then B must be telling the truth. However, if B is telling the truth then A must also be telling the truth. This is a contradiction, so C must be telling the truth.

share|improve this answer

edited 8 hours ago

tom

2,14811 gold badge77 silver badges3030 bronze badges

answered 9 hours ago

HeavpootHeavpoot

2122 bronze badges

New contributor

Heavpoot is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.

$endgroup$

• 
  
  
  

  
  

  
  
  
  
  
  

  
  $begingroup$
  Welcome to Puzzling SE. Note that I put some formatting into your answer so that the answer would not be obvious. You did a nice job of hiding your explanation though. I had to put some words in to make the formatting work.
  $endgroup$
  – tom
  8 hours ago
  

  
  
  
  

add a comment
 | 

$begingroup$

I think the answer is

C.

because

If C is lying, then B must be telling the truth. However, if B is telling the truth then A must also be telling the truth. This is a contradiction, so C must be telling the truth.

share|improve this answer

edited 8 hours ago

tom

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answered 9 hours ago

HeavpootHeavpoot

2122 bronze badges

New contributor

Heavpoot is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.

$endgroup$

share|improve this answer

edited 8 hours ago

tom

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answered 9 hours ago

HeavpootHeavpoot

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New contributor

Heavpoot is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
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edited 8 hours ago

tom

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edited 8 hours ago

tom

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answered 9 hours ago

HeavpootHeavpoot

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answered 9 hours ago

HeavpootHeavpoot

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