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What are the Odds?

Trick brain teasers appear difficult at first, but they have a trick that makes them really easy.

 

Puzzle ID:#49666
Fun:*** (2.76)
Difficulty:** (1.86)
Category:Trick
Submitted By:christiangrl*us*****

 

 

 



If you choose to answer this question at random, what are the chances you will be correct?

A) 25%
B) 50%
C) 60%
D) 25%



Answer

0%

If you were to choose 25%, that would be wrong, because there are two 25% answers, giving you a probability of 50%, which is also not possible, because the answer 50% is only offered once as an option. It's a probability paradox!

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Comments

kitty-catAus*
Nov 18, 2012

First comment!

Great teaser, I got it simply because I read too many trick brain teasers.

I saw the name in the new teasers section and luckily glanced at the category before answering. I thought it was probability at first.
ursulanqtus*
Nov 20, 2012

Nice one!! Of course me being me I said 25%. Aren't I amazing!!!
dangerouspie101tus*
Nov 23, 2012

Awesome, cg!
supernova12tus*
Nov 24, 2012

I love your teasers! They're all very creative and and perfect in every way!
Quocalimar*
Nov 24, 2012

bwuuuuuuuuuuuh. I got it wrong and still don;t get it after reading the answer. That was extremely clever.
Viperus*
Nov 25, 2012

The correct answer is B.
The question is phrased "IF you choose to answer this question at random." 50%!
kitty-catAus*
Nov 28, 2012

But if the correct answer is B, then you DON'T have a 50% chance of getting it right. If the answer is 50%, then the answer is actually 25%, but then it would be 50, and it's an endless loop, a paradox.
christiangrl*us*
Nov 28, 2012

Thank you kitty.
Thekid4t*
Dec 05, 2012

Okay, I see the paradox, but why is the answer 0%? Shouldn't it be "there is no answer" or "paradox"? Either way, great teaser.
sarah12lizbeth*
Dec 08, 2012

I thought that as well, Viper. 50%. Hmmm...
ObilioAus*
Dec 11, 2012

cool I think, lol
sashomarineAus*
Mar 22, 2013

That's really smart
JQPublic**
Apr 19, 2013

Thanks, my brain really hurts now. Great teaser.
SaraGracetus*
Jul 31, 2013

I liked this one
kitykity1t*jm*
Aug 06, 2013

this just scrambled my brain and served it with toast.Wheat toast.
Babe*
Jan 06, 2014

I have no idea. Thi9s must be a young person's riddle.
Babe*
Jan 06, 2014

Oops! #9 does not belong in there. It just snuck in when I was not looking.
HABS2933Aca*
Jan 06, 2014

Pretty easy, but enjoyed it.
FarFetched
Jan 06, 2014

The correct answer should be among the options for answering.
catmomAus*
Jan 06, 2014

huh? need...more....coffee
dsjtus*
Jan 06, 2014

I chose to not answer this question at random.
jandjfrench*
Jan 06, 2014

It seems that if I choose to answer the question at random and do answer the odds that I've correctly answered are 100% (sure thing). Just sayin'!
Zykezex*us*
Jan 06, 2014

Isn't the odds of choosing A or D 33.333...% (one out of three) 25%, 50%, 60%?
Zykezex*us*
Jan 06, 2014

I mean 33.333% choosing A or D and being correct...
spikethru4*au*
Jan 07, 2014

Zykezex: The probability of picking A or D is 2 out of 4, not 1 out of 3. Don't forget that "25%" is twice as likely as the other two options because it appears twice.

FarFetched: That's the trick. If the "correct answer" were an option, you'd still get a paradox, e.g.

What are the chances of picking the correct answer?
A) 25%
B) 50%
C) 60%
D) 25%
E) 0%

...but clearly you can pick E 20% of the time so it's no longer correct.
Zykezex*us*
Jan 07, 2014

A thought: If I couldn't see the answers, A&D are 2/4. Having seen 25% twice, my choices narrowed to 1/3. (25%, 50% or 60%). The chances of being correct are still zero as 33.333% wasn't an answer for A or D.
spikethru4*au*
Jan 09, 2014

That's a fair comment, but the point is you're answering at random, so the choices are (A, B, C, D), not (25%, 50%, 60%).
ultimatecubtgb*
Nov 30, 2014

Wow...that's a great teaser! I love paradoxes
Eminem*in*
Jun 20, 2015

50% is the probability
TheRiddleTrollAus*
Dec 11, 2016

On second thought, this belongs in the logic category.

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