Logic Puzzle
Saw this and wanted to share:
If you choose an answer to this problem at random, what is the chance that you will be correct?
A) 25%
B) 50%
C) 0%
D) 25%
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(12 votes, average: 4.75 out of 5)Send to Kindle (12 votes, average: 4.75 out of 5)
April 27th, 2012 at 7:42 pm
Ever notice that all paradox questions involve asking you to predict the future?
April 27th, 2012 at 7:45 pm
I am Nomad. I am perfect.
April 27th, 2012 at 7:45 pm
Before I answer, I need to know:
1) Are you Sicilian?
2) Is death on the line?
April 27th, 2012 at 7:56 pm
@Harvey: what is your prediction for “this statement is a lie” ?
April 27th, 2012 at 7:58 pm
Where is none of the above?
April 27th, 2012 at 8:04 pm
Capitalist_B – depends… are you a Democrat?
April 27th, 2012 at 8:05 pm
Also, C) might work if you can show your work, thus proving it wasn’t a random selection.
April 27th, 2012 at 8:05 pm
@Harvey: one of these men always lies and one always tells the truth but BOTH are insisting that the other one is a liar and a Democrat…
April 27th, 2012 at 8:07 pm
Is suicide an option?
April 27th, 2012 at 8:11 pm
one of the men replies “Suicide is immoral.” The other man replies “I do not support the right to voluntary doctor assisted life termination.”
April 27th, 2012 at 8:35 pm
How about murder? Is murder ok?
April 27th, 2012 at 9:08 pm
The suicide question was better for telling them apart. “I support your right to bear arms!” they both cheerily reply.
April 27th, 2012 at 9:08 pm
The answer is “The rent is too damn high!”
April 27th, 2012 at 9:23 pm
100%
That was easy.
April 27th, 2012 at 9:48 pm
B),
Random simulations will result in 25% of picking each answer.
25% – A is “correct”
25 % – B is “wrong”
25% – C is “wrong”
25% – D is “correct”
Therefore, you’re 50% to pick the correct answer, and so B is correct. But if B is correct, then you’re only 25% likely to pick the actual correct answer, and so the answer is a and d. But if A and D are correct, then you’re 50% likely to pick the correct answer, and so B is the correct answer….HEAD EXPLODES.
April 27th, 2012 at 9:49 pm
The most common way to create a paradox is with a self referential statement like this one. Self referential statements are not “logical statements.” They don’t have either a value of true or false. Same is true about statements about the future. (Self referential statements are usually implicit statements about the future.) “The Broncos will win their first regular season game” is not at this time true or false (unless you believe in predestination). It has a probability of being true. “If you pick the answer at random” is the same idea.
April 27th, 2012 at 9:51 pm
They should have posed this question to Colossus. Perhaps that would have prevented the machine from being the VOICE OF WORLD CONTROL. Or maybe it would have resulted in this:
ACTION WILL BE TAKEN.
April 27th, 2012 at 10:09 pm
I think probability guys would say A and D are considered distinct and therefore are each correct as if they were different. So either is right. And then they get a wedgie.
April 27th, 2012 at 11:00 pm
what is the airspeed velocity of a laden swallow?
April 27th, 2012 at 11:59 pm
African or European?
April 28th, 2012 at 12:39 am
If i don’t choose an answer I have 100% chance of not being wrong.
April 28th, 2012 at 12:55 am
Capt. Kirk: Everything Harry tells you is a lie.
Harry Mudd: Listen to this carefully, Norman. I am lying.
April 28th, 2012 at 6:27 am
Inconceivable!
April 28th, 2012 at 8:27 am
No matter how I answer it my taxes will still go up. Ditto if I don’t answer it.
April 28th, 2012 at 8:49 am
C
April 28th, 2012 at 8:49 am
C
April 28th, 2012 at 9:16 am
If I choose one of four possible answers at random, what is the chance that I will choose one of the four answers at random?
If I do X, what is the chance that I have done X? 100%, by definition.
____________________
Actually, after spending hours trying to suss this out with long explanations, I think I’ve condensed it pretty well.
The puzzle is unanswerable.
If there is a 25% chance of choosing the correct answer, then it can’t be A or D, because there is a 50% chance of selecting either of those two.
If there is 50% chance of choosing the correct answer, then it can’t be B, because there is a 25% chance of selecting it.
If there is a 0% chance of choosing the correct answer (even though there is no correct answer), then it can’t be C, because there is a greater than 0% chance of selecting it — 25%
My head hurts.
This lie takes the cake.
Excuse me, one of my hands is clapping.
A monk asked Obama: “Does a dog have Buddha Nature?”
Obama barked back: “Yum!”
April 28th, 2012 at 10:18 am
Now, after doing a search and looking at different wordings of the puzzle elsewhere, I should qualify that I interpret the question to mean that the answer is supposedly among the four options, and that there is an equal chance of hitting any one of them.
Here’s one discussion of a similar problem, with “60%” as answer C, and the author seems to interpret it similarly — favoring the conclusion that the answer would be 0%, but that there would be no solution if C were 0% — described in conclusion #3 on this page: http://understandinguncertainty.org/probability-paradox
April 28th, 2012 at 12:29 pm
If we were liberals it would be much easier to answer this question, because the right answer would be “whatever MSNBC said the answer was.”
April 28th, 2012 at 2:47 pm
Son of Bob: And they’d get a participation trophy.
April 28th, 2012 at 5:41 pm
When you break it out, you’ve only got 2 answers – 50% or 25%, since we can eliminate 0%.
So my guess is (B) 50%.
April 28th, 2012 at 6:05 pm
This problem is conditional on what the correct answer is. The way I see it the answers themselves are inconsequential and also misleading. Recast the question thus:
If you choose an answer to this problem at random, what is the chance that you will be correct?
I am assuming that “the problem” is not actually stated here.
1) a
2) b
3) c
4) a
The probability is dependent on the correct answer. If the correct answer is “a” then the probability is 50%. If “b” or “c” the probability is 25%. That is, you can only figure the probability if you know what the correct answer is.
How’s that?
April 29th, 2012 at 2:11 am
If you try arguing the probability of the other answers being right then you are falling into a trap. You are actually figuring the probability of the them being picked.
Since there can be no correct answer, the only correct answer is C. 0%. And the universe now implodes.
April 29th, 2012 at 11:13 pm
It could be argued that choosing an answer at random is not an attempt to make a determination at all and can therefore not be correct. Any agreement between an unintentional mark and reality is happenstance or coincidence. You may get credit in a test but so would a monkey– a chinese monkey.
The answer is c because a random answer doesn’t address the question.
IF you didn’t even read the question, how can you be correct?
April 30th, 2012 at 9:50 am
The Answer is of course, 42.