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How smart is /b/?

The stories and information posted here are artistic works of fiction and falsehood.
Only a fool would take anything posted here as fact.

Thread replies: 112
Thread images: 20

File: coinsprob.jpg (45KB, 370x277px) Image search: [iqdb] [SauceNao] [Google]
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How smart is /b/?
>>
75% dude
>>
>>724909739

1/3
>>
50%
>>
nigger
>>
>>724909739
50% you fucking faggot with your middle school trick question.
>>
50% ofc
>>
25 percent u fuckin nignogs. each coin has 2 sides so 1 out of 4
>>
File: coinsprobfags.png (16KB, 590x491px) Image search: [iqdb] [SauceNao] [Google]
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>>724910111
>>724910013
>>724910263
>>724910313

Laugh at the stupid people.

They deserve it.

The answer is 1/3, you retarded faggots.
>>
1/2 and 1/3

>because OP sucks black cock and posts deliberately vague questions with not enough information for a definite answer and touches his penis watching faggots argue which logic path to the answer is the right one, when he knows they both are
>>
>>724910037
Expanding
I could use the formula and shit but there are just 4 possible outcomes so I'll skip that.

HH, HT, TH, TT

At-least one head is a given, so we remove TT.

HH, HT, TH

only one out of the three has both heads.

1/3
>>
>>724910037
Only guy here who can do combinatorics.

There are 4 possibilities: HH HT TH TT, all are equal. When you eliminate one (TT), the remaining probabilities are still equal, and only 1 of the three is the desired outcome (HH), so 1/3.
>>
75%
>>
>>724910462
You must exclude all cases without heads before calculating. It is a given in the problem.
>>
>>724910575

That's what he did, dumbass.
>>
>>724910477

>basic conditional probability question
>vague

kek

Nah, you're just retarded.

1/3
>>
This is the stupidest fucking thread. I didn't know how many people could fail at high school mathematics.

The set of all possibilities {HH, HT, TH, TT}
The required set{HH, HT, TH}
75% U autist fucks
>>
>>724910761


Faggots falling for thid, both 1/2 and 1/3rd are correct you morons, you're arguing over OOOOOOLD bait for OPs amusement because the question deliberately doesn't have enough information for either answer to be wrong
>>
>>724910930
*66%
>>
>>724909739
50/50 shot. Kys op
>>
>>724910943

I am OP. There is one correct answer. The correct answer is 1/3.

You're an idiot.
>>
>>724910943
It's 1/3 u stupid fuck
>>
>>724909739
50:50
if one of them is given, its like flipping only one coin. two possible outcomes, 50%
>>
>>724911027
Fucked it again 33%
>>
>>724911095
You're right, and so is 1/2, because the question is a logical paradox
>>
>>724910575
H=heads T=tails
>>
File: Uni_Wash_Cond_Prob.jpg (137KB, 921x631px) Image search: [iqdb] [SauceNao] [Google]
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>>724911207

there isn't enough information to get 1/2 as an answer, you retard.

there is enough information to get 1/3.

Therefore 1/3 is the correct answer.

Pic Related: Source
http://courses.cs.washington.edu/courses/cse312/11wi/slides/04cprob.pdf

1/3

REKT
>>
>>724909739
Painful to see so many people brag about getting it wrong. It's 1/2, not 1/3. One coin is definitely heads, that leaves heads and tails or both heads as possibilities. Wow.
>>
>>724910930
what is the probably both landed heads
>both
>BOTH

was special school not special enough?
>>
>>724911120
>>724911120

there are 3 equally lkely ways to get at least 1 heads.

heads, heads
heads, tails
tails, heads

1/3
>>
>>724911120
but it's not said which one is given.
>>
>>724911207
>logical paradox

It's basic conditional probability, you thick cunt.

use Bayes' theorem to solve.
P(A|B) = P(A∩B)/(P(B))

Explanation for faggots:

COnditional probability questions take the form:
>What is the probability of Event A given Event B?

OPs question is
>What is the probability that BOTH coins landed heads, given that AT LEAST ONE coin landed heads?

So here

A = "both coins are heads" = {(HH)} = 1/4
B = "at least one coin is heads" = {(HH), (HT), (TH)} = 3/4

P(A|B) = P(A∩B)/(P(B)) = (1/4)/(3/4) = 1/3
>>
>>724910462
>being this retarded
h and t, t and h are the same thing, you fucking retard, so it's 1/2. HAHAHAHAHA how can you make a table, see that two are the same and still come up with 1/3.
>>
>>724911526

If not trolling, Kill yourself.
>>
>>724909739

Oh look, it's this thread again.

>simulation
/thread
>>
>>724909739
that depends.
is op a fag?
odd means yes
even means no
>>
>>724911698
>h and t, t and h are the same thing,

you are a retarded motherfucker.

Penny=heads, Quarter=tails
is not the same as
Penny=tails, Quarter=heads

You fail at logic and math, retard.

1/3
>>
you faggots always think that it would be 1/2 for each side but you suck at math like you probably do in sports. there IS a fucking chance that a coin lands on the side and stands. i've seen this when i was 9. i threw a coin and it landed on the fucking side!
PLUS there is nearly no coin on this planet which sides do exactly have the same possibility to land on. now kiss my feet and the ground i walk on.
>>
>>724911678
>It's basic conditional probability, you thick cunt.
No it isn't because it brings the problem into a real life situation rather than just being a set of figures
>>
>>724911821
It's got nothing to do with the side landing you mongoloid. Assume both coins land normally.

Go flip 2 coins 30 times and get back to me.
>>
>>724911821

coin stopped your aging, apparently
>>
>>724911821
This is what the math autists never understand - the physical world affects things and so pure mathematical working is pointless when you're talking about real objects
>>
1/3

$ python3 test.py
0.3331260766659477

gist.github .com/anonymous/d9208d1031348382d313bd2df8756880
>>
>>724911977
>Assume
That is not how the world works
>>
File: cond.gif (939B, 266x94px) Image search: [iqdb] [SauceNao] [Google]
cond.gif
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P(A and B) = 1/4
P(A) = 3/4
P(B|A) = (1/4) ÷ (3/4) = 1/3
>>
>>724910037
At least 1 Head?
-->75%
>>
>>724912012
>>724912055

oh look its the tardarmy
>>
>>724912012
>pure mathematical working is pointless when you're talking about real objects

>math doesn't apply to the real world

kek you fucking retards.

1/3
>>
>>724912208
given one head
question is both head
>>
>>724909739
Once you're given the fact that one of them is always heads, it does not count as a probability. It is a given. You are left with only calculating the single coin, heads or tails. And that is 50%
>>
It's a 1/3 chance but if ya want it in percentage its would be 33.33333333333%
>>
>>724912012
>>>724911821
>This is what the math autists never understand - the physical world affects things and so pure mathematical working is pointless when you're talking about real objects

What
>>
>>724909739
Not smart enough. Majority favor Trump.
>>
>>724912521
>one of them is always heads
It isn't.

>it does not count as a probability.
It does.

>You are left with only calculating the single coin
Nope. there are 2 coins.

2 coins, 3 equally probable ways to get at least 1 heads

heads - heads
heads - tails
tails - heads

1 of 3

1/3
>>
File: 1478788896289.png (762KB, 850x616px) Image search: [iqdb] [SauceNao] [Google]
1478788896289.png
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100 %.
You know why? Because when I roll up in this thread, heads will roll on the floor.
>>
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1/2 * 1/2 = 1/4
>>
>>724911550
the question says that "at least one of them landed heads"
>landed
so you already have HT or TH. it doesnt matter which one.
therefor it remains a 50% chance that the other one landed heads too.
>>
File: coins3.jpg (18KB, 470x342px) Image search: [iqdb] [SauceNao] [Google]
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>>724912758
>the question says that "at least one of them landed heads"
>>landed
Correct.

>so you already have HT or TH
or HH

3 equally likely outcomes possible.

HH is 1 of them.

1/3

Stay in school.
>>
>>724910761
And just like your own diagram says, there's also not enough information to provide 1/2 is wrong either, can you prove that the first coin was flipped first and landed heads? Can you say that one was even flipped before the other or both flipped at the same time? The question doesn't specify therefore neither possiblity 1/2 or 1/3 is wrong
>>
>>724912284
That's not what I said retard. Of course maths applies to the real world but you have to take account of the extra factors when dealing with real objects - a real life coin is NOT 50/50 heads/tails for one thing, and the given in the scenario means physical tampering in order to create a certainty. This shouldn't be so hard to understand
>>
>>724912980
you guys must be trolling - NO ONE is this stupid
>>
>>724913114
you are
>>
>>724912688
One of them is always heads in the case we are to consider. It is given in the problem. You can restate the problem as, "Given that you have a picture of a coin on the table that is heads up, what is the probability that you will have two coins on the table heads up if you flip another coin?"
>>
>>724909739
HAHAAHAHAHAHA "what is the probability that both are heads, given that one definitely is"
>1/3

HAHAHAHAHAHA LMFAOOOOO
>>
>>724913114

>I don't understand conditional probability
>I'll just say they're stupid or trolling

kek
>>
In mathematics it will always be true that (1/2)+(1/2)=1 but in the real world if you cut a baby in half then place the pieces next to each other you don't still have the same thing you started with. Reality matters, and moving mathematical problems into reality means you have to take these things into consideration
>>
>one is heads, the other is either heads or tails
>chance of both being heads, 50%

/b/ everyone...
>>
Do you cunts realize this is completely different to Monty Hall problem?
>>
>>724911419
No one knows Bayesian analysis...

Comp sci major and professional programmer, here. It is , indeed, 1/3.
>>
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>>724913478
>one is either heads or tails, the other is heads
>>
>>724913304
>One of them is always heads in the case we are to consider
Incorrect. Either coin could be tails, just not both at the same time. This gives us 3 equally probable outcomes that all satisfy the condition of having at least 1 heads. Why is this so hard for you to grasp.

Flip 2 coins. At least 1 landed heads. So you could have:
coin1=Heads, coin2=Heads
or
coin1=Heads, coin2=Tails
or
coin1=Tails, coin2=Heads

1/3

>Given that you have a picture of a coin on the table that is heads up, what is the probability that you will have two coins on the table heads up if you flip another coin?

That's a diffrent question, because you are fixing a specific coin as heads. OP question does not fix any specific coin. Either coin could be tails. In your scenario, 1 of the coins cannot possibly be tails. That is the difference.

The answer to your question is 1/2

The answer to OP question is 1/3.
>>
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>>724912758
This. To make it a non-retarded trick question, it should be presented as "Blah blah blah, assuming at least one coin will always land heads?", which would obviously somewhat reduce the trickiness.
>>
>>724913658
It's 2 coins you moron. You're thinking of what happens if you just tape one down as heads and flip the other. That's not how it works.
>>
>>724913745
nigger that's what i was explaining to the other niglet
>>
>>724913696
>basic conditional probability question
>trick question

No wonder you think the answer is 50%. You're retarded.

Answer is 1/3
>>
ONE COIN ALREADY LANDED HEADS

YOU HAVE ONE COIN SHOWING HEADS

THERE IS ONLY ONE INDIFFERENT COIN LEFT

THIS INDIFFERENT COIN HAS ONLY 2 SIDES

THEREFOR A 50:50 CHANCE OF SHOWING HEADS TOO
>>
File: 1R7XXkJ.png (57KB, 625x656px) Image search: [iqdb] [SauceNao] [Google]
1R7XXkJ.png
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https://en.wikipedia.org/wiki/Boy_or_Girl_paradox
>>
>>724913696

In fact, the answer to OP's question in indeed 1/2, because it says "landed". If landed were to be replaced by "will land", the answer would be 1/3.
>>
>>724914046
>this tard rage

kek

There are 3 ways to get at least 1 heads coin, dumbfuck.

1/3
>>
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>>724914053
Shit, you beat me to it.
>>
>>724914139

You're an idiot.

I just flipped 2 coins. At least 1 landed heads.

What's the probability that both landed heads?

Protip: It's 1/3
>>
It's 50% and anyone who thinks otherwise is fucking retarded.
>>
>>724909739
50% you fucking idiots, the first coinflip doesn't matter. Say you get heads on your first coin, now you have a 50/50 chance of either getting heads or tails on the second coin
>>
>>724914310

>Retard calling others retarded

kek
>>
>>724914394
>the first coinflip doesn't matter.

What makes you think the first coin is the heads coin, dumbass?

1/3
>>
>>724914053
>https://en.wikipedia.org/wiki/Boy_or_Girl_paradox

Watch this be ignored, even though it's all right there.
>>
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>>724913745
The OP's setting is deliberately worded poorly so as to imply that one coin's resulting value is known before the other's. Since the coins are not assumed to be indistinguishable, this permutation is then known to be either "T H" or "H T", leaving the odds at this point to be 50%. since the result of the toss actually decides which coin's value is revealed. Sort of like a monty hall thingy going on. That's what makes this a "trick question", the deliberately poor wording.
>>
Morons it doesn't matter if 1 coin flips head or tails, because 1 coin is a guaranteed 100% chance to flip heads therefore this one becomes kinda irrelevant. Now you have 1 coin left and it either flips head or tails which is a 50% chance. There's no other solution, and there's only 2 options. Either H - H or H - T
>>
>>724909739
1/4th you niggers
>>
>>724914683
you are smart
>>
>>724914683
>deliberately worded poorly

Nah, it's a clear basic conditional probability question. the reason people think it's 1/2 is because they are shit at conditional probability as it's counter-intuitive.

>Since the coins are not assumed to be indistinguishable, this permutation is then known to be either "T H" or "H T", leaving the odds at this point to be 50%.

What the fuck are you talking about. 2 coins flipped. At least 1 is heads. That gives 3 possible outcomes, all of which are equally likely:
HH or HT or TH

1/3

No tricks, just dumbasses who can't solve basic conditional probability questions.
>>
>>724914701
>Either H - H or H - T
or T - H

1/3
>>
>>724914993

IT'S IN THE WIKI ARTICLE. ACADEMICS, ACTUAL MATHEMATICIANS, RECOGNIZE THAT THE QUESTION IS AMBIGUOUS.

Fuck, these threads trigger me so hard. 8/8, OP.
>>
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>>724914993
>What the fuck are you talking about.
If one coin holding the H value is revealed, it eliminates either the "H T" or the "T H" scenario, leaving the odds then at 50%. Very similar to the monty hall problem case. Without such a revelation, the chance is indeed 1/3.
>>
>>724915439

It's not ambiguous. Read the article. you can only get an answer of 1/2 if a child is selected and its gender is specified.

that's not what happens in OP question, retard.

See pic related

If the FIRST coin landed heads, teh probability is 1/2.

If AT LEAST 1 coin landede heads, the answer is 1/3.

OP question = 1/3
>>
>>724915040
>or T - H
No because the scenario calls for at least one coin to 100% be heads. That means one of either TH or HT is rendered impossible. Again, it's down to how putting the theoretical into the physical changes things
>>
>>724915623
>If one coin holding the H value is revealed

But it isn't, you fucking raging tard. you don't know WHICH coin landed heads, meaning EITHER coin could be tails, just not both.

Let me explain this as easily as I can so even simpletons can understand.

When you flip 2 coins, there are 3 (THREE) equally probable ways to get AT LEAST 1 Heads coin. Do you agree or disagree?

If you agree, great, you're not completely retarded. If you disagree, the rest of this post will make no sense to you.

So, 3 equally probable outcomes satisfy the condition of having AT LEAST 1 heads. These are:

Heads - Heads
Heads - Tails
Tails - Heads

Both heads is 1 of those 3.

1/3
>>
>>724915750

T - H contains at least 1 heads, dumbass.

It satisfies the condition.

1/3
>>
>>724915750
>Again, it's down to how putting the theoretical into the physical changes things

No, slowpoke.

if you think that the answer is not 1/3, take 2 coins and flip them 100 times in real life.

Count how many times you get at least 1 heads (~75)
Count how many times you get 2 heads (~25)

25/75 = 1/3

REKT again.
>>
>>724916040
You aren't understanding the point. In order for there to be 100% chance of at least 1 being heads as per the question, one coin must be 100% guaranteed to be heads. If that's the first coin, TH can't happen, and if it's the second, HT can't happen
>>
>>724916175
>Count how many times you get at least 1 heads (~75)
Except that this question says that the answer to this question is 100
>>
File: coins1.jpg (35KB, 370x277px) Image search: [iqdb] [SauceNao] [Google]
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>>724916188
>In order for there to be 100% chance of at least 1 being heads as per the question, one coin must be 100% guaranteed to be heads.

Incorrect. 2 coins were flipped and at least 1 landed heads by chance.
it was never guaranteed, and as you don't know WHICH coin landed heads, it remains possible that EITHER coin could be tails.

You fail at logic, because you can't understand how EITHER coin could still be tails, giving 3 equally likely outcomes.

For anyone who still thinks the answer is 50%, answer pic related.

Protip: it's 1/3
>>
>>724916240
>Except that this question says that the answer to this question is 100

What?
>>
It IS guaranteed because the original question says that at least one has to be heads. This is not difficult
>>
>>724916421
Your pic related is a different question based on something that's already happened rather than just probabilities
>>
>>724916600

No.

2 regular coins were flipped. At least 1 landed heads.

If I flip a coin and it lands heads, it wasn't GUARANTEED to land heads. it simply landed heads by chance.

If I flip 2 coins and at least 1 landed heads, I could have any 1 of 3 equally likely possibilities

Heads - Heads
or
Heads - Tails
or
Tails - Heads

3, 1 of which is both heads.

Do you disagree?
If you do, explain why.

1/3
>>
>>724916421
Nah it should be (1/2)x(1/2)=0,25
>>
>>724916774
By the way the question is worded, one at least IS guaranteed heads. It says it right there in words. Doesn't matter which one, because in either case it knocks out the possibility of either TH or HT.
>>
File: coinsss.jpg (53KB, 360x640px) Image search: [iqdb] [SauceNao] [Google]
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>>724916754

>tails - tails isn't the result
is equivalent to saying
>at least 1 landed heads

So you're incorrect. the answer to both is 1/3.

We know that tails-tails is the only option not possible in OP question, because it does not satisfy the condition of having at least 1 heads coin.

the other 3 equally likely outcomes DO satisfy the condition, and are therefore all relevant and included.

In both questions, only tails-tails is excluded.

1/3
>>
>>724916966

HT and TH are both possible as they both contain at least 1 heads.

HH is also possible as it contains at least 1 heads.

That's 3 equally likely outcomes containing at least 1 heads.

1/3
>>
File: 435.png (37KB, 658x662px) Image search: [iqdb] [SauceNao] [Google]
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>>724915893
>But it isn't, you fucking raging tard. you don't know WHICH coin landed heads
Yes, I know. My point was, the OP's question was needlessly poorly worded (such as the non-standard use of past tense, which might to some imply that it is indeed known which coin rolled heads)
>Let me explain this as easily as I can...
Everyone who's not trolling understands that already, no need to repeat it like it's some magnificient explanation of einstein's field equations. I have not contested the truth of that statement at any point, I even explicitly agreed with it in my previous post just to make sure you would not misunderstand, which you still somehow managed to do. The point here is, and always was, the somewhat ambiguous wording in the OP.
>>
The only way to make the question work is by one coin (at least) being 100% heads. Without that, tails tails would be possible and the question itself won't work
Thread posts: 112
Thread images: 20



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