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Quiz about Liars Scoundrels and Logicians
Quiz about Liars Scoundrels and Logicians

Liars, Scoundrels, and Logicians Quiz


There is a strange land with a surprisingly high crime rate, but the inhabitants are more often compelled to always tell the truth or a lie, rather than look out for their own well-being. Can you use your logical wits to survive this strange land?

A multiple-choice quiz by qrayx. Estimated time: 24 mins.
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Author
qrayx
Time
24 mins
Type
Multiple Choice
Quiz #
395,955
Updated
Dec 03 21
# Qns
10
Difficulty
Difficult
Avg Score
4 / 10
Plays
186
Question 1 of 10
1. Through some very unjust laws, you have been convicted of a horrible crime. But the king knows that good logicians are always innocent, so you've been given a way out. You get to choose which knight will carry out your sentence. One knight is the Knight of Life, who will set you free, and will always tell the truth. One is the Knight of Death, who will immediately execute you, and will always lie. Lastly is the Knight of the Dungeon who will lock you up for the rest of your days, and will sometimes lie and sometimes tell the truth. You get to ask each knight one question, so:

You ask the red knight, "Who is the green knight?", to which she says, "He is the Knight of Life."

You ask the blue knight, "Who is the green knight?", to which she says, "He is the Knight of the Dungeon."

You ask the green knight, "Who are you?", to which he says, "I am the Knight of Death."

Who is the Knight of Life?
Hint


Question 2 of 10
2. Proving that you are an innocent person, and excellent at logic, you are recruited into the king's detectives to help solve other crimes. In this village, it is known that at a crime scene, liars are always guilty and truth-tellers are always innocent.

On your first day, you and your partner, Detective Sleuth, head out to your first crime scene where three individuals have been detained for questioning. Sleuth gets their statements.

Alice says, "Bob is guilty!"

Bob says, "Two of the three of us are innocent."

Carl says, "Yeah, Alice and I are innocent!"

Whom should you arrest?
Hint


Question 3 of 10
3. On your second day with the king's detectives, you visit another crime scene, where again, truth-tellers are always innocent and liars are always guilty. There are three suspects for this crime. Sleuth decides to see how you'll do, and lets you take the statements from the suspects.

Dianne says, "At least two of us are innocent."

Edgar says, "Dianne and Felicia are both innocent."

Felicia says, "Edgar and I are the same type."

Note: Felicia is saying she and Edgar are both truth-tellers, or both liars.

Whom should you arrest?
Hint


Question 4 of 10
4. On your third day, you and Detective Sleuth visit another crime scene with only two possible suspects. You know that liars are always guilty and truth-tellers are always innocent.

Greg says, "At least one of us is innocent."

Detective Sleuth turns towards Heather and asks, "Is Greg innocent?"

Heather mutters something that you don't quite hear, but Sleuth is now convinced she knows what happened.

Whom should you arrest?
Hint


Question 5 of 10
5. On your fourth and final day of training with Detective Sleuth, you walk to yet another crime scene. Once again, liars are guilty and truth-tellers are innocent. The first two suspects are very loud and agitated, clamouring over each other to give their statements.

Isaac says, "Jessica and Keith are both liars!"

Jessica says, "No, Isaac is a liar!"

Detective Sleuth turns towards Keith and calmly asks if Jessica is innocent. Keith responds so softly that you miss his answer, but Sleuth is now certain she knows what happened.

Whom should you arrest?
Hint


Question 6 of 10
6. With your training over, you are sent away to assist the detectives of Scoundrelville, where truth-tellers are not always innocent, and liars are not always guilty.

On your first day, you arrive at the crime scene. Only one of the suspects is guilty, and you know that all of them are liars.

Laura says, "It's all Mike's fault. Mike is guilty!"

Mike stays calm and says, "Naomi is innocent."

Naomi sneers and says, "Laura is the guilty one."

Whom should you arrest?
Hint


Question 7 of 10
7. On your second day in Scoundrelville, you are brought to a slightly more complicated set of suspects. Of the three of them, only one committed the crime, and only one is telling the truth, but it is not necessarily the same person. With a projected air of confidence, you speak to each of the suspects.

Oscar vehemently declares, "I am innocent!"

Penny, in a smaller voice, also says, "I am innocent."

Quentin, flustered, sputters and says, "No, Oscar is guilty!"

Whom should you arrest?
Hint


Question 8 of 10
8. On your third day, you are taken to a similar scene, with three suspects. Only one of them is guilty, and only one of them will tell you the truth.

Ruby runs up and quickly says, "Samson is innocent."

Samson nods enthusiastically and says, "It is Tiffany who is guilty."

Tiffany sighs, and says, "Yes, it was me. I'm guilty."

Whom should you arrest?
Hint


Question 9 of 10
9. With some more experience under your belt, you have been permitted to look at more complicated cases. Again, a crime has been committed by only one person, and only one of the suspects is telling the truth, but this time there are four of them. Despite the added complexity, you know you can solve this, and ask for statements from the suspects.

Ulysses says, "Vivian is innocent."

Vivian says, "Agreed. It was definitely Wallace or Xena who committed this crime."

Wallace turns red and yells back, "Ulysses is the one who did it!"

Xena keeps her eyes low and refuses to say anything.

Whom should you arrest?
Hint


Question 10 of 10
10. On a bright morning with an inexplicable sense of finality, you head off to work to solve yet another crime in Scoundrelville. You arrive at the scene to find all four witnesses loudly bickering with one another. Without any prompting, they turn to you to each tell you what they think. You know that only one of them is telling the truth, and that only one of them committed the crime.

Yvonne says, "Zadie is guilty."

Zadie says, "Britney is innocent."

Aaron says, "Yvonne and Britney are both innocent."

Britney says, "That's right, because you're guilty."

Whom should you arrest?
Hint



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Quiz Answer Key and Fun Facts
1. Through some very unjust laws, you have been convicted of a horrible crime. But the king knows that good logicians are always innocent, so you've been given a way out. You get to choose which knight will carry out your sentence. One knight is the Knight of Life, who will set you free, and will always tell the truth. One is the Knight of Death, who will immediately execute you, and will always lie. Lastly is the Knight of the Dungeon who will lock you up for the rest of your days, and will sometimes lie and sometimes tell the truth. You get to ask each knight one question, so: You ask the red knight, "Who is the green knight?", to which she says, "He is the Knight of Life." You ask the blue knight, "Who is the green knight?", to which she says, "He is the Knight of the Dungeon." You ask the green knight, "Who are you?", to which he says, "I am the Knight of Death." Who is the Knight of Life?

Answer: The blue knight

This is often called the Three Knights problem. The classic responses have been tweaked to not make this question an exact copy.

Starting with the final statement, the green knight cannot be the Knight of Life. If asked who they were, the Knight of Life would have to tell the truth, saying they are the Knight of Life. So the red or blue knight must be the Knight of Life.

The Knight of Life would never say a different knight was the Knight of Life, but that's what the red knight did.

The only option left is the blue knight.

The blue knight is the Knight of Life, and told you the green knight is the Knight of the Dungeon, which means the green knight lied when he said he was the Knight of Death. The red knight must then be the Knight of Death, who lied when she said the green knight was the Knight of Life.
2. Proving that you are an innocent person, and excellent at logic, you are recruited into the king's detectives to help solve other crimes. In this village, it is known that at a crime scene, liars are always guilty and truth-tellers are always innocent. On your first day, you and your partner, Detective Sleuth, head out to your first crime scene where three individuals have been detained for questioning. Sleuth gets their statements. Alice says, "Bob is guilty!" Bob says, "Two of the three of us are innocent." Carl says, "Yeah, Alice and I are innocent!" Whom should you arrest?

Answer: Bob and Carl

Starting with the first statement, we know that Alice and Bob are different (one is a truth-teller, and one is a liar). If they were both truth-tellers, then Alice's statement would be a lie (a contradiction). If they were both liars, then Alice's statement would be the truth (also a contradiction).

From Bob's statement, we know that he is a truth-teller, along with Carl, or he is a liar, and only Alice is a truth-teller. So Bob and Carl must be the same type, which means Carl and Alice must also be opposite types.

When Carl claims he and Alice are the same type, we know he is a liar. Thus, Carl and Bob are both liars, and Alice told the truth.
3. On your second day with the king's detectives, you visit another crime scene, where again, truth-tellers are always innocent and liars are always guilty. There are three suspects for this crime. Sleuth decides to see how you'll do, and lets you take the statements from the suspects. Dianne says, "At least two of us are innocent." Edgar says, "Dianne and Felicia are both innocent." Felicia says, "Edgar and I are the same type." Note: Felicia is saying she and Edgar are both truth-tellers, or both liars. Whom should you arrest?

Answer: None of them

The first statement means Dianne cannot be the only truth-teller, or the only liar.

The second statement means that either all three people are truth-tellers, or they are all liars, or Felicia is the only truth-teller.

We look at all three states with Felicia's statement in mind. If all three were liars, then Felicia's statement would be true (a contradiction). If Felicia was the only truth-teller, then her statement would also false (another contradiction). The only state with no contradictions is when all three people are truth-tellers.
4. On your third day, you and Detective Sleuth visit another crime scene with only two possible suspects. You know that liars are always guilty and truth-tellers are always innocent. Greg says, "At least one of us is innocent." Detective Sleuth turns towards Heather and asks, "Is Greg innocent?" Heather mutters something that you don't quite hear, but Sleuth is now convinced she knows what happened. Whom should you arrest?

Answer: Only Heather

Before considering any statements, we'll acknowledge four possible states: Greg is the only truth-teller, Heather is the only truth-teller, they are both truth-tellers, or they are both liars.

Greg's statement does not allow for him to be a liar and for Heather to be a truth-teller (he'd be telling the truth, which is a contradiction). So we're only concerned with the three remaining states, and will consider Heather's response.

If they were both liars, then Heather would have responded, "Yes."

If they were both truth-tellers, then Heather would have responded, "Yes."

Lastly, if only Heather was a liar, then she would have said, "No."

Because the last state has a unique answer, when Sleuth knew for certain, so did we.
5. On your fourth and final day of training with Detective Sleuth, you walk to yet another crime scene. Once again, liars are guilty and truth-tellers are innocent. The first two suspects are very loud and agitated, clamouring over each other to give their statements. Isaac says, "Jessica and Keith are both liars!" Jessica says, "No, Isaac is a liar!" Detective Sleuth turns towards Keith and calmly asks if Jessica is innocent. Keith responds so softly that you miss his answer, but Sleuth is now certain she knows what happened. Whom should you arrest?

Answer: Isaac and Keith

From the first statement we know that Isaac is either the only truth-teller, or at least one of the other two is a truth-teller. They cannot all be liars.

Jessica's statement means that she and Isaac are different types (one is a liar, and one is a truth-teller).

We now have three possible states: Isaac is the only truth-teller, Jessica is the only truth-teller, or Jessica and Keith are both truth-tellers.

We'll consider the possible responses Keith gave to these states:

If Isaac was the only truth-teller, then Keith would have said, "Yes."

If Jessica was the only truth-teller, then Keith would have said, "No."

If Jessica and Keith were both telling the truth, then he would have said, "Yes."

Again, only one state had a unique answer, which is how Sleuth was able to be certain after hearing Keith's answer.
6. With your training over, you are sent away to assist the detectives of Scoundrelville, where truth-tellers are not always innocent, and liars are not always guilty. On your first day, you arrive at the crime scene. Only one of the suspects is guilty, and you know that all of them are liars. Laura says, "It's all Mike's fault. Mike is guilty!" Mike stays calm and says, "Naomi is innocent." Naomi sneers and says, "Laura is the guilty one." Whom should you arrest?

Answer: Naomi

You actually only need one statement: Mike's.

Mike said Naomi was innocent, but you know he's a liar, which means Naomi is guilty.

Because only one person is guilty, the other two statements can also be verified as lies.
7. On your second day in Scoundrelville, you are brought to a slightly more complicated set of suspects. Of the three of them, only one committed the crime, and only one is telling the truth, but it is not necessarily the same person. With a projected air of confidence, you speak to each of the suspects. Oscar vehemently declares, "I am innocent!" Penny, in a smaller voice, also says, "I am innocent." Quentin, flustered, sputters and says, "No, Oscar is guilty!" Whom should you arrest?

Answer: Penny

From the first statement, we can tell that Oscar is either telling the truth and innocent, or is guilty and lying (not a great revelation when dealing with crooks).

Penny makes a similar statement, and we can draw a similar conclusion.

These two statements together, though, do something interesting: Quentin cannot be telling the truth. If Oscar was guilty, then Penny would be telling the truth. If Penny was guilty, then Oscar would be telling the truth. If Quentin was guilty, then both Oscar and Penny would be telling the truth (a contradiction, because there is only one truth-teller here).

So, knowing that Quentin is a liar, when he claims Oscar is guilty, we know that Oscar is actually innocent and the sole truth-teller. Therefore Penny must be a liar and the real culprit.
8. On your third day, you are taken to a similar scene, with three suspects. Only one of them is guilty, and only one of them will tell you the truth. Ruby runs up and quickly says, "Samson is innocent." Samson nods enthusiastically and says, "It is Tiffany who is guilty." Tiffany sighs, and says, "Yes, it was me. I'm guilty." Whom should you arrest?

Answer: Ruby

Samson and Tiffany are saying the same thing (that Tiffany is guilty), but only one person can be telling the truth. This means they are both liars, and Tiffany is actually innocent.

Ruby must be the truth-teller, and she said Samson was innocent. Unfortunately for her, that leaves Ruby herself as the only possible criminal.
9. With some more experience under your belt, you have been permitted to look at more complicated cases. Again, a crime has been committed by only one person, and only one of the suspects is telling the truth, but this time there are four of them. Despite the added complexity, you know you can solve this, and ask for statements from the suspects. Ulysses says, "Vivian is innocent." Vivian says, "Agreed. It was definitely Wallace or Xena who committed this crime." Wallace turns red and yells back, "Ulysses is the one who did it!" Xena keeps her eyes low and refuses to say anything. Whom should you arrest?

Answer: Vivian

Ulysses' statement actually makes things quite easy for us. Either he is the truth-teller, or Vivian is guilty.

Vivian then goes on to accuse Wallace or Xena of committing the crime. Unfortunately, if Wallace or Xena committed the crime, that would make both Vivian and Ulysses truth-tellers (which is not allowed).

The only possible states now are that Ulysses is telling the truth and that he is guilty, or that Vivian is guilty, and one of the other two is telling the truth.

Wallace then says Ulysses is guilty. If Ulysses was guilty, then both he and Wallace would be truth-tellers (again, not allowed), so Wallace is a liar.

The only possible solution now is that Vivian is guilty, and Xena is the only truth-teller (despite not having to say anything at all).
10. On a bright morning with an inexplicable sense of finality, you head off to work to solve yet another crime in Scoundrelville. You arrive at the scene to find all four witnesses loudly bickering with one another. Without any prompting, they turn to you to each tell you what they think. You know that only one of them is telling the truth, and that only one of them committed the crime. Yvonne says, "Zadie is guilty." Zadie says, "Britney is innocent." Aaron says, "Yvonne and Britney are both innocent." Britney says, "That's right, because you're guilty." Whom should you arrest?

Answer: Yvonne

Similar to the previous question, we're going to let the second statement do a lot of work for us. Either Zadie is telling the truth, or Britney is guilty.

Next, Yvonne's statement. If Zadie was guilty, then both Yvonne and Zadie would be telling the truth, which is a contradiction. Yvonne cannot be a truth-teller, which means Zadie is definitely innocent. We still don't know if Zadie is telling the truth or not.

Some quick accounting shows us the remaining possible states:

- Zadie is telling the truth, and either Yvonne or Aaron is guilty.

- Britney is guilty, and either she or Aaron is telling the truth.

Aaron claims that Yvonne and Britney are both innocent, so either he's telling the truth, or one of them committed the crime. We've halved our number of possible states, down to two:

- Zadie is telling the truth and Yvonne is guilty

- Britney is guilty and telling the truth

Finally, Britney claims that Aaron is guilty, which means she cannot be telling the truth. Zadie must be telling the truth, and Yvonne must be guilty.
Source: Author qrayx

This quiz was reviewed by FunTrivia editor Fifiona81 before going online.
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