The Off Topic Topic

[Josquius]

Thats a trap for computers isn't it?
25% would be correct with 4 different ones which means its 50% which means its not 25% which means....
Yeah... I guess 0 is a saver since there is no correct answer.... but wait. Then that means its 25%....

Not real I hope?

[DGuller]

For the learned folk of Languish who understand probabilities better than I do.

[Habbaku]

 

[Admiral Yi]

What's the question?

[Liep]

Thats a trap for computers isn't it?
25% would be correct with 4 different ones which means its 50% which means its not 25% which means....
Yeah... I guess 0 is a saver since there is no correct answer.... but wait. Then that means its 25%....

Not real I hope?

Isn't it just C though?

[Maladict]

Thats a trap for computers isn't it?
25% would be correct with 4 different ones which means its 50% which means its not 25% which means....
Yeah... I guess 0 is a saver since there is no correct answer.... but wait. Then that means its 25%....

Not real I hope?

Isn't it just C though?

That's what I thought.

[Agelastus]

There's Quora Threads on the subject, one of which has about 380 replies.

This "question" has been around since at least 2011.

Looking at a few of the answers one could almost write a philosophical tract about the issues around the puzzle and its' wording.

[Not that I'm interested enough to wade too deeply into the issue.]

[Agelastus]

Thats a trap for computers isn't it?
25% would be correct with 4 different ones which means its 50% which means its not 25% which means....
Yeah... I guess 0 is a saver since there is no correct answer.... but wait. Then that means its 25%....

Not real I hope?

Isn't it just C though?

https://www.quora.com/If-you-choose-an-answer-to-this-question-at-random-what-is-the-chance-you-will-be-correct-A-25-B-50-C-60-D-25

[Apparently the question is out there in forms that give 60% instead of 0% as the fourth answer, and the order of the answers is altered. Some of the replies have notes that they have amended various bits of their answer as the question changes over the years.

[Malthus]

The trick here is the assumption one of the answers must be correct. None are in this case.

Proof: there are four answers one can pick, so the odds must be one of 0%, 25%, 50%, 75% or 100%.

0% isn't a possible answer. The reason: there is an answer that is 0%, and so it can be chosen; there is a 25% chance of picking it at random.

25% isn't a possible answer. The reason: there are two of them, so there is a 50% chance of choosing it.

50% isn't a possible answer. The reason: there is only one of it, and so only a 25% chance of choosing it.

75 and 100% are not choices.

[Richard Hakluyt]

The trick here is the assumption one of the answers must be correct. None are in this case.

Proof: there are four answers one can pick, so the odds must be one of 0%, 25%, 50%, 75% or 100%.

0% isn't a possible answer. The reason: there is an answer that is 0%, and so it can be chosen; there is a 25% chance of picking it at random.

25% isn't a possible answer. The reason: there are two of them, so there is a 50% chance of choosing it.

50% isn't a possible answer. The reason: there is only one of it, and so only a 25% chance of choosing it.

75 and 100% are not choices.

Yes, here is a variant that is more obvious :

Who is the current monarch of the UK?

A. Henry IV
B. Charles II
C. William the Conqueror
D. Henry IV

[Barrister]

The trick here is the assumption one of the answers must be correct. None are in this case.

Proof: there are four answers one can pick, so the odds must be one of 0%, 25%, 50%, 75% or 100%.

0% isn't a possible answer. The reason: there is an answer that is 0%, and so it can be chosen; there is a 25% chance of picking it at random.

25% isn't a possible answer. The reason: there are two of them, so there is a 50% chance of choosing it.

50% isn't a possible answer. The reason: there is only one of it, and so only a 25% chance of choosing it.

75 and 100% are not choices.

But the question isn't "which is the correct answer".  The question is "if you select at random, what are the odds you'll select the right answer".  Which is C - 50%.

[Syt]

The trick here is the assumption one of the answers must be correct. None are in this case.

Proof: there are four answers one can pick, so the odds must be one of 0%, 25%, 50%, 75% or 100%.

0% isn't a possible answer. The reason: there is an answer that is 0%, and so it can be chosen; there is a 25% chance of picking it at random.

25% isn't a possible answer. The reason: there are two of them, so there is a 50% chance of choosing it.

50% isn't a possible answer. The reason: there is only one of it, and so only a 25% chance of choosing it.

75 and 100% are not choices.

But the question isn't "which is the correct answer".  The question is "if you select at random, what are the odds you'll select the right answer".  Which is C - 50%.

But if C is the right answer, the chance of landing on it is only 25%

[celedhring]

The trick here is the assumption one of the answers must be correct. None are in this case.

Proof: there are four answers one can pick, so the odds must be one of 0%, 25%, 50%, 75% or 100%.

0% isn't a possible answer. The reason: there is an answer that is 0%, and so it can be chosen; there is a 25% chance of picking it at random.

25% isn't a possible answer. The reason: there are two of them, so there is a 50% chance of choosing it.

50% isn't a possible answer. The reason: there is only one of it, and so only a 25% chance of choosing it.

75 and 100% are not choices.

But the question isn't "which is the correct answer".  The question is "if you select at random, what are the odds you'll select the right answer".  Which is C - 50%.

But you only have 25% of selecting that one.

[Josquius]

I guess you have to ignore what the answers actually say and arbitrarily one of them is right so it must be 25%?

[Malthus]

The trick here is the assumption one of the answers must be correct. None are in this case.

Proof: there are four answers one can pick, so the odds must be one of 0%, 25%, 50%, 75% or 100%.

0% isn't a possible answer. The reason: there is an answer that is 0%, and so it can be chosen; there is a 25% chance of picking it at random.

25% isn't a possible answer. The reason: there are two of them, so there is a 50% chance of choosing it.

50% isn't a possible answer. The reason: there is only one of it, and so only a 25% chance of choosing it.

75 and 100% are not choices.

But the question isn't "which is the correct answer".  The question is "if you select at random, what are the odds you'll select the right answer".  Which is C - 50%.

Exactly. And if you select that, it incorrect, because the odds of selecting that are only 25%.

It's self-referential, which is why there is no correct answer.