How smart is /b/?

>>727088338
0.5

2/4

>>727088478

Wrong.

Try again.

>>727088650
I know for a fact that I am not wrong

1/3

>>727088338
It's ambiguous.
Can be either 1/2 or 1/3, depending on how you find out that one coin in heads.
According to Maya Bar0Hillel and Ruma Falk (1982), "Some teasers concerning conditional probabilities," and Raymond S. Nickerson (May 2004), Cognition and Chance:The Psychology of Probabilistic Reasoning.

Educate yourselves.
https://en.wikipedia.org/wiki/Boy_or_Girl_paradox

>>727088338
Given that one of them is guaranteed to be heads, it gets eliminated from the formula altogether, making it just the other coin, so 1/2.

1/4

In a real world? 1/2. Either it happens, or it doesn't. There's too many variables.

In a logical ideal world? 1/3

100% because the question asks "when they both land heads"

TT
HH
TH
HT

There are 4 possible flips, so 1 out of 4

>>727088991
>>727088939
>>727088873
>>727088846
>>727088786
>>727088764
>>727088650
>>727088629
>>727088478
Retards, read pic.

>>727088338

>gambler's fallacy

50%

100 % because it literally states "when both laned heads"

>>727089070
oh you fuckin' got us

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>>727089070
fucc

>>727089070
Better post this again in an hour so you can call everyone a retard some more as way to compensate for your own stupidity :)

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100%

100 percent, because they are connected by quantum entanglement.

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>>727089070

>>727089110
>>727089123

top kek

They're Euro coins. They don't have heads duhh.

>>727089070

It's still 1/3 in a logical ideal world, you twat.

HT,TH,HH,TT

We know TT can't happen since one lands heads. Then we have 3 possibilities left, where only 1 is HH.

/thread

>>727089450
You're both wrong, the pic literally states "When both land heads"
Off yerselves

The question is poorly written. But in effect, it's 50% considering it's given that one lands heads.

>>727089496

Can you not read?

"What is the probability that both landed heads [question, indetermined] given that at least one of them landed heads [statement, determined]?"

>>727089450

Thank you anon, I thought I was the only mathematically sane person in here!

>>727088338
Benedict Cumberbatch

50% = fact. Unless accounting for weight diffetential on each side makes it 50.1 or something. Each flip's probability is independent of any other flips. One is heads, so we're looking at the independent probability of the other flip. It's no more or less probable just because of the first flip's result. Thus, flip 2 is 50/50, or 50%.

>>727089496
>>727089110
What the actual fuck are you talking about?

>>727089772

Hey I posted 1/3 you fuck.

>>727089883

Except, you're wrong. One of the coins lands heads, but we don't know which one. So the answer is 1/3, or 33.33%

>>727089941
dyslexia.

>>727090062
not the guy you responded to.
It doesnt matter. The coins are the same. TH is the same as HT. it's given that one coin lands H, doesn't matter whether it's the first or second one.

Bayes' theorem of conditional probability states the following:
let H be heads
let T be tails

P(H)=P(T)=0.5
let A be first heads
B second heads
P(A/B)=(P(A)*P(B/A))/P(B)
=0.55*0.25/0.5=0.25=1/4

>>727089450

mate. TH HT cannot be counted as distinct events in this context. As we know one H has already been revealed, these are equivalent you fecking numpty

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>>727088478
>>727088629
>>727088764
>>727088873
>>727088939
>>727088991
>>727089038

All wrong.

The answer is 1/3.

Flip 2 coins. At least 1 landed heads.
3 equally likely outcomes contain at least 1 heads:
Heads, Heads
Heads, Tails
Tails, Heads

So 1/3

>>727088846
Question in OP is not a paradox. It's a basic conditional probability question. There is no trick. The reason its used as b8 is because morons think the answer is 50%.

1/3

>>727090400

TH and HT are equivalent once H has been revealed.

50pc

>>727090347
0.5*0.25/0.25=0.5 ***

>>727090273
>>727090354

>doesn't understand logic

>>727089883
It says "at least one of them". We've no idea of the state of the first coin: maybe only the second coin lands on head.

And yes, the difference between "one of them" an "the first one" has an impact on the result. It's one of these weird cases where the human mind has a false intution.
See https://en.wikipedia.org/wiki/Boy_or_Girl_paradox

1/3.

OP is being a faggot about this, though.

>>727090354

no, they are 2 separate and distinct outcomes, both containing at least 1 heads coin, just like HH contains at least 1 heads coin.

HH, HT, TH all possibl>>727090354
and equally likely.

1/3

>>727090502

Neither coin is revealed until the flip is done. All we know is that at least one of them will be H - not which one.

>>727090400
what a moron

H has already been revealed it's literally just looking for

P(H knowing that first roll was H)
P(H/H1)

>>727090676

is this honestly bait?

you cannot see that TH and HT once one state is know are absolutely equivalent?

>>727090273
not the guy you responded to.
it does matter tho. HT, TH, and HH are equally likely. if you know it's one of them, the chance is 1/3.

>>727090502
>TH and HT are equivalent

No, they're not, you dumbass.

Flip a penny and a quarter. At least 1 landed heads. You could have

P=Heads, Q=Heads
or
P=Heads, Q=Tails
or
P=Tails, Q=Heads

All equally likely. All contain at least 1 heads. All separate and distinct outcomes.

1/3

>>727090752
>P(H knowing that first roll was H)

First could be tails, you retarded fuck.

HH, HT, TH

1/3

>>727090989
you're right, I apologize, Anon.

>>727091387

Welcome to the dark side, anon.

>>727090765

It's not bait, just conter-intuitive mathematics.

TH and HT are equivalent as result, but that doesn't matters.

We've 4 states: TT, TH, HT, HH
All we know is that the result is not TT. So it can be one of TH, HT, HH.
-> the probability of a HH state is 1/3

The probability of TH or HT (which are the same) is 1/2

>>727088338
1/4

>>727091507
>The probability of TH or HT (which are the same) is 1/2
Arf, I means 2/3

0%. Those are euros they dont have fucking heads on them.

>>727091507

Everything is correct, except your last sentence. The probability of HT is 1/3, and the probability of TH is 1/3. With HH being 1/3, we get 100% combined.

And thus the world will not collapse because of a missing probability.

>>727091636
>which are the same

Actually, most do.

>>727088338

Euro coins aren't "regular" coins per se. Mathematically speaking, a regular coin would be the coin most used in a population.

A Chinese coin would have been more correct.

>>727092316
Maybe the euros are just pictures not related to the question ?

>>727091744
>the world will not collapse because of a missing probability
Who know ? Maybe we're in a False Vacum world, and there is a probability the world collapse itself at any time.

>>727092457

not the same guy.
or maybe the question is just text not related to the flipped coins?

>>727088338
>Both landed heads
P(HH)=0.25

>>727092937

>ignores the condition

Fucking pleb.

>>727089450
correct

>>727092815

Maybe the text is just a list of unrelated words put together ?

Damn OP, he know how to bait!

It is 1/3 if the coins were different somewhat.
As the question doesn't specifies it (and show two equal coins), the logic answer is 1/2.

>>727094564

If not b8, kill yourself.

>>727094622
>you should kill yourself just because I can't think in an rebuttal to prove you wrong.

Prime example of fags using shit like this to fuck w ppl on the internet, while technically yeah there's TH and HT, what differentiates between the two of them if theyre turned over at once, are the coins different or labelled? If not then it can be presumed to be interchangable and therefore equivalent and since the coin only has two sides the answer determined by common sense is 50%, but then again this is /b/ and theres not a lot of common sense around

0.5, the events are independent

>>727094767

>thinks the coin being similar or different makes a difference to the probability
>hurr Durr u have n-n-no rebuttal dUrr

Monumentally stupid people aren't deserving of a rebuttal, kiddo. Just ridicule and pleas to neck yourself. At the very least never have kids.

>>727094897
>TH and HT, what differentiates between the two of them
They are 2 separate and distinct outcomes, each with a 1/3 probability of occurring, yu utter simpleton.

1/3

>>727095292
Which is still substantially greater than your chances of getting head fag

>>727090400

You moron. The bottom left part of the pic has also been discounted when the first coin is revealed as heads. The options are narrowed from TT, TH, HT, HH to HH, HT. How can you have option for both TH and HT when it has been clearly stated that the first coin is heads. The remaining options are thus HH, or HT. 0.5 in other words

ITT: people calling each other morons

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>>727095588

HT = 1/3
TH = 1/3
HH = 1/3

1/3 for all, faggot.

What's it like being a retard?

>>727095682
>when the first coin is revealed as heads.
>first coin

First coin could be tails, you stupid cunt. Work on your reading comprehension.

HH, HT, TH all valid and all equally likely.

1/3

42

>>727095160
It does make a difference.
If I know which coin is given to heads, I can simply ignore the part (whatever you want) of HT or TH, because they aren't equivalent.
Now, is easy to try feeling like a superior by saying "kiddo", "neck yourself" or shit like that just to not explain your point.

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>>727096868
>If I know which coin is given to heads

That's not what you said originally, you stupid fuck. Stop moving the goalposts. And you DO NOT know which coin landed heads from the question.

>is easy to try feeling like a superior by saying "kiddo", "neck yourself" or shit like that just to not explain your point.

I've explained it multiple times, you retard, but simpletons like you are either too stupid to read the thread or just can't grasp basic conditional probability math.

Explanations are here:
>>727096449
>>727090989
>>727090895
>>727090400

Neck yourself, kiddo.

1/3

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One of the two coins lands heads, no matter which one or how, it's out of the question.
So what are the odds of the other coin to land heads?
1/3 Head
1/3 Tails
1/3 Tie
33%
We can now kill ourselves in peace faggots

>>727088338

50%

If you're given the basis that at least one -will- land on heads, then that percentage no longer affects the outcome. The second coin holds all the chance with it.

Its 50/50

>>727089095
you fucking imbred its not P(A&B) its P(A|B).
0.33

>>727097895
>The second coin holds all the chance with it.

First coin could be tails, retard.

1/3

>>727097394
>And you DO NOT know which coin landed heads from the question.
Yes, that is why I used a two-way answer, it's ambigous.
Stop being a flat-egoed person, you are the tipical loser who feels the urge to inferiorize others to feel superior over a "simple" thing, like you said.