I know that /b/ can't solve this, because you're a

50% ya faggot

>>719982742
1/3

>>719982742
50% faggot

fiddy fiddy ya cunt

>>719982785
You are a dumb motherfucker man.

Explain your reasoning?

monty hall problem jajajajaja

>>719982742
1/3

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>>719982865
Don't do it anon, let him stew.

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>>719982878
That's with three hallways and removing one after picking. That's not the same problem at all fag.

>>719982865
If one of them is already heads, then its just a coin flip ya cunt

>>719982865
It either happens or it doesn't.

>>719982906
>>719982799

So if I throw a coin and it lands on heads....there is a 1/3 chance that the second coin I'll throw after that is heads too?

You fuckers are beyond retarded, how quickly would you be fooled in a street bet?

>>719982925
faggot

>>719982742
If one of them has landed heads, the probabilty of the other one landing is 51%, as per regular coin toss.

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>>719982951
You a pussy ass bitch, I told you to let them niggers figure it out on their own.

>>719983020
Shhh, now they know I wasn't lying to fool the dumbasses

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>>719982951
>>719982992
No, there is a difference between:
T H
H T
They are seperate instances, they are collectively more likely to occur than a H H.

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>>719982878
I still can't buy stuff

>>719982993
> So if I throw a coin and it lands on heads....there is a 1/3 chance that the second coin I'll throw after that is heads too?

That's not the question being asked. read again

Every time I see you in my Catalog, you fat, unkempt, disgusting excuse of a "man", I want to reach through the monitor and shoot you. As in, murder you with a fucking pistol.

You are everything wrong with humanity. You are an affront to everything humans strive for. You are a disgrace to those who pushed themselves mentally, physically and emotionally beyond what they thought was possible, to achieve heights never before reached in their chosen endeavour.

I hate you. I literally hate you. Why don't you fucking kill yourself?

>>719983081
Nice drawing faggot, let me explain why you are wrong.

Imagine the 'guaranteed' head was the first coin. Then the odds are:
H H
H T

In which case there's a 1/2 chance of both getting heads.

If the second coin was the guaranteed heads, the options are:
H H
T H

In which case there's STILL a 50% chance of getting two heads.

So the odds are 1/2

>>719983080
Doesn't matter, if one of them is 100% heads, the second is a coin flip, and if the second one turns out to be heads then you already failed, so it's still 50/50 ya dumbass motherfucker

>>719983177
fresh pasta?

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>>719983207
Nope. Imagine you throw 2 coins 100 times.
You will get:
H H : 25 times
T H : 25 times
H T : 25 times
T T : 25 times

Since you KNOW that in this particular instance, at least 1 coin was heads, you can scrap the T T.

That leaves an equal 25/75 chance for every other scenario to occur, so there's a 1/3 chance to get H H.

>>719983080
Go back to your elementary school math hour ya dumbass, and learn to draw

>>719982742
1/3.

potential choices:
coin 1 heads coin 2 tails
coin 1 heads coin 2 heads
coin 1 tails coin 2 tails
coin 1 tails coin 2 heads
All options have equal chances of occurring as is noted by the "regular coin" bit, implying fair chance.

Discard the both tails option (fulfilling requirement of "given that at least one of them landed heads") - you are left with 3 equally probabilistic results, of which only 1 is both heads.

Therefore, p(both coins=heads) = 1/3. QED.

If it helps, visualize one coin as a quarter and one as a nickel, and treat them as separate entities. It works the same even if they are indistinguishable, but for the sake of demonstration, distinguishing them can help.

>>719983207
>>719983309
You are implying that you throw the second, unknown coin AFTER it's been confirmed that at least one of the heads is coin. That's not the case.

>>719983296
Dude, 33.33:66.66 is 1/3 not 25:75 ya dumbass motherfucker

>>719982742
The Euro doesn't have heads.

Just bottoms

https://youtu.be/G-6QU5pPSfs

>>719982742
>>719983189
I don't think you can split it up, because now you have 2 times 'HH'.

It is a single throw of two coins with at least one being heads, so there are three possible outcomes:
HT
TH
HH

Obviously, chance of HH is 1/3.

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>>719983369
1/3 and 25/75 are the exact same thing faggot.

Its 75% !!!

>>719983415
TH and HT would both result in the phrase 'At least one of them in heads', so they are counted together.

The second coin is either heads or tails, and this happens as a seperate instance, previous throws have no influence over the second coin. It's an independent action.

So 50% that that one is heads too.

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If you know that the coins are fair and the tosses are independent, and if the "given at least 1 head" is strictly interpreted (you know that, and just that), your answer is correct. A priori (without the additional "at least 1 head" condition), you had four equiprobable cases. The condition removes one of the four possible cases, but does not say anything more (hence the three remaining cases remain equiprobable). Hence, the probability of the case "2-heads" is 1/3.

>>719983415
>I don't think you can split it up, because now you have 2 times 'HH'.
>I don't think you can split it up
>I don't think

Yeah you seem really sure about yourself. Maybe you should let the intelligent people do the thinking.

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100%
The heads side of the coin is heaver than the tails, making it impossible for the coin to land with the heads side facing up.

Facts given:
>two were flipped
>one landed heads (100% prob)
>the other landed heads (50% prob) or tails (50% prob)

Were only flipping one coin. First coin is always heads. So ww need the probbability of two coins being heads after one is always heads! If one is already always heads....

Does chaos theory apply to this?
What side did the coin start on?
Is it a cheap coin? can it flip?
What are the chances it lands on its rim?
What's the calculation of air resistance during the flip?

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>>719983624
Your fat ass is heavier than your head as well, does that mean if you jump of a cliff, you cannot reach the bottom headfirst?

Stupid fuck.

Also, since no information is given, you can assume they are standard untampered coins.

Its all going cashless m80
there is no chance € will land anywhere after the union falls apart.

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>>719983743
The heavier side always falls to the bottom. It is impossible for a coin to naturally land on tails

>>719982742
Straightforward Bayes Theorem. P(heads|one is heads) = (.5²)/(.75) = .33333. So 1/3.

stats minor here

>>719983739
>Does chaos theory apply to this?
That applies to anything, so yes.

>What side did the coin start on?
Probably heads, so the viewer could check the value.

>Is it a cheap coin? can it flip?
The intrinsic value is 22 eurocents. The market value is 1 euro. It can flip.

>What are the chances it lands on its rim?
Same chance as you receiving a rim job from Emma Watson.

>What's the calculation of air resistance during the flip?
The experiment takes place in a vacuum.

>>719983929
Two coins are flipped, one is heads.
Basically you can get rid of the first heads, and the question would practically be:

'What's the chance this 1 coin will land on heads?'

Then it becomes obvious that the answer is 50%. The first coin doesn't matter, it's a trick question.

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you guys make me sick. calculate it

.25/.75 = 1/3

>>719982742
0% because no one uses real fucking money anymore jesus christ dude how fucking old are you

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>>719983964
>stats minor
>too stupid to link to his own post

50 percent bitch

>>719983517
No they are not. Since they are two independent coins, HT and TH are considered different possible outcomes. Given "at least one is heads" means we only remove the possible outcome of TT. So we have three possible outcomes, HH, HT, and TH. Only one outcome out of the possible three gives two heads, so it is 1/3.

This is and has been discussed to death by actual mathematicians, with intense reasoning and arguing on both sides for a very long time. Read up on boy-girl paradox, Bertrands box, or Monty hall problem. All are along the same idea. The given information changes the situation, and the correct answer goes against your intuition. Hey here are some links to make it easier! But no one will read or care and still keep arguing on this forever though. That's why these are such good threads.

https://en.m.wikipedia.org/wiki/Boy_or_Girl_paradox
https://en.m.wikipedia.org/wiki/Bertrand's_box_paradox#/search
https://en.m.wikipedia.org/wiki/Monty_Hall_problem

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Who wants more pocket mons?

if one landed up on face then it is out of the equation. your left with one coin that is heads or tails which means theres a 50 percent chance of it being heads. at this point its only one coin

>>719984196
>Monty Hall problem

Good thing you brought it up. The answer to the monty hall problem is 50%. Thanks for making a fool of yourself.

>>719982742
p=0.5

Next?

>>719984196
Read this:
>>719984314

I can't make it any simpler for you faggot.

>>719983080
No you fucking autistic bastard. It either happens or it doesn't. That's it. There's nothing more to it. If you can't get this through your head then you have mental issues.

>>719984314
You have just proven that you are a dingus who doesn't understand the problem or question being asked.

>>719984359

weak b8 is weak

>>719984479
I meant to link >>719984312

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>>719984416
Finally someone who's not retarded.

>>719984518
that's not how this works. that's not how any of this works.

c1 = 100%
c2 = 50%
probability = (c1/c2)^2

>>719982742
4 outcomes, 00 01 10 11, each 0.25 probability, however 00 is out. So the remaining 3 have each 1/3 probability. Out of these only 11 qualifies, so it's 1/3.

>>719984771
>4 outcomes, 00 01 10 11, each 0.25 probability
>each 0.25 probability

T H and H T both have 0.50 probability
That leaves 1 - 0.50 = 0.50 probability for H H.

It's 75%. Half (50%) has already landed and is guaranteed. The other 50% is split into a 50/50 chance of landing. Half of 50 is 25. So that would be a 75% chance.

>>719984905
What the French fuckery are you saying

H T
T H
HH

1/3 what is that? Hurrr durrr I'm a millenial who can't math

>>719985198
head tails you fucking imbecile

>>719982742

Considering these are Euros, the Jews/EU will take the other coin anyway.

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>>719985101
Team A: It's 1/2
Team B: It's 1/3
This faggot: It's 75% guys! Hodor

>>719985275
Not even making since you autist

>>719985198
You can't ignore the T T just because it's not valid. It still covered a 1/4 chance on the initial throw. You can't just remove outcomes when it's convenient for you.

>>719985419
You can when the problem states there is a heads you inbred retarded piece of shit, are you still in school?

>>719983080
One possibility has already happened.

>>719985419
You can and do when it's given that at least one came up heads. It's not asking for probability before the throw, it is asking after, when you are being told that TT did not happen.

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>>719985295

>>719985497
Chronologically:
1. The throw happened, each outcome 1/4 chance.
2. The 'announcer' claims at least 1 coin is heads.

Since the throw happens BEFORE the statement, that means every scenario was taken into consideration already. That 1/4 doesn't vanish retroactively, what's in the past cannot be changed.

1/2 you stupid fucking bunch of cunts, accept it

>>719985725
We aren't talking about before the statement you fucking idiot. Have you ever had a math word problem, learn to read. They eliminated tails tails. Are you fucking b8in m8?

>>719985787
Prove it.

No matter how many times you flip a coin, it will always have a 50% chance of landing heads. 5 coin flips that land heads in a row is just as likely as 5 coinflips that land as heads, heads, tails, heads, tails.

>>719985787
You cockadoodle cunt, it doesn't said heads was flipped first hence it saying given one of them landed heads. Could be any fucking order

HH
TH
HT

1/3 autist millenial

>>719985930
Now this is autism volume 200

>>719982742

Each coin is 50% to land on heads, but it's 33% that both are heads. How you ask? Well there's a 33% chance of two tails, 33% chance of two heads, and a 33% chance of one head and one tail. Anyone who says anything else is retarded.

>>719985969
You fucking nigger, I spent a day in college learning this shit, fuck off.

>>719985725
You are missing
3. The question is asked.

There are only three possible outcomes since 2. removed the TT outcomes. Only one is HH. 1/3.

>>719985934
>what is the probability that both landed heads given that one has landed heads
Can you fucking read?

>>719982742
50

>>719986048
Yes because if you throw 100 coins in the air the probability doesn't change by amount of coin vs result. Better get a refund on that education you inbred piece of shit

Seriously are you guys retarded
the set is {HH,HT,TH,TT}
required both heads HH
so 1/3 as fourth is all tails

>>719982742
Seriously are you guys retarded
the set is {HH,HT,TH,TT}
required both heads HH
so 1/3 as fourth is all tails

>>719986048
You spent all day in college learning that the odds of head or tails in a coin flip is 50-50? You went to a special college didn't you? Also, the answer to this question is 1/3.

>>719986137
Can you fucking read? It doesn't say that one was flipped first.

Flip two coins (no tails tails)

Coin one heads and coin two tails
Coin one head and coin two heads
Coin one tails and coin two heads

Are you fucking that dumb?

This thread is incompetent

YOU FUCK BOYS
IF ONE IS GUARANTEED TO BE HEADS ITS AS
IF BOTH SIDES OF THAT COIN IS HEADS SO
ITS DEPENDENT ON THE OTHER COIN WHICH IS ASSUREDLY 50 50 CHANCE

>>719986260
>Are you retarded
Posts the same thing twice

>>719986329
See>>719986291
You god damn inbred fuck

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>>719986015
>m8?
>>719986114
>>719985934
>>719985198
Too all these fuckers who think it's 1/3.

Here's the same problem except more tangable (it doesnt require abstract thinking, so it's easier for you morons)

SEE PIC

When you get pregnant, there's a fifty/fifty chance of getting a boy or girl. If you know the first was a girl, what's the gender of the second child?

YOU STILL DONT KNOW. The chance of gettinga boy or girl is still 50%, it's a seperate event.

If you admit that the solution to pic related is 50%, you should also admit that that's the solution for the coin problem, because it's exactly the same.

If you still think it's 1/3, then you admit that you think a mother of a baby girl has a 1/3 chance of getting another baby girl when she gets pregnant again, when it's obviously 1/2.

100% and then some

>>719986310
Plus, this thread belongs to FB.

>>719986389
YES YES YES YES

>>719986329
No it is not. It is either only coin 1 is heads, only coin 2 is heads, or both are heads.

>>719986389
You added a very special word there you very special dumb mother fucker "first"

>hurrr durr let me prove them wrong with a whole different problem

Millenial logic

>>719983369
1/3 isn't 25/75


wut

/b/ - A place for teenage boys to pretend they're astrophysicists and put each other down while answering their homework since 2003.

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>>719986498
I could have drawn the girl as the secon child and it wouldn't change the problem.

IT DOESNT MATTER on which side the girl is. Jesus christ, you are dense.

>>719986479
BUT YOU SAID THAT COIN 1 IS HEADS SO ITS DEPENDANT ON WHETHER COIN 2 IS HEADS
POSSIBLE OUTCOMES: HT HH

I admit, I thought it was 50%, but now I see it's 1/3. Sorry for being a fucking retard for a minute

=>>719986349
yeah sorry
>>719986329
>>719986389
Read the question dumb basement dwellers
What is the probability that both landed heads
{Heads,Heads}
So in set of
{Heads,Heads/Heads,Tails/Tails,Heads/Tails,Tails}
Prob for not second one but both is
req/(all possible pairs)
=HH/(HH,HT,TH,TT)
1/4
Answer

>>719986614
>>719986614
>>719986614
>>719986614
SAME FAGGOTRY

SAME FAG

>>719986593
Then you just changed it again you inbred dumb piece of shit

Then your problem becomes. Okay wife is having twins what's the chance both are boys?!?!

Child one boy child two girl
Child one boy child two boy
Child one girl child two boy

You're completely removing the variable that each one has a probability you stupid nigger

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>>719982742
66% idiots

>>719986627
so wait of course it is
but thats only if you calculated the odds before first coin is flipped

>>719986720
genetics becomes a whole different kettle of fish as far as probabilities go, man. bad example.

>>719982742
0 = heads
1 = tails

combos that exist: 00, 01, 10

11 is invalid

therefore,

1/3

have we done your HW 4 u yet

NO WERE GETTING BAITED
IM OUT

(.5*.5)/.5 = .5

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>>719986720
Ok, happy now? The answer is still the same.

The chance of a kid you haven't seen yet being a boy or girl is still 50%. If it's a girl, that means there will be 2 girls, which is the same as 2 heads in the original question.

Dense fuck.

>>719986389
See you are right in this question. It says THE FIRST CHILD is a girl. This coin question does not say which coin is heads, only that AT LEAST one of them is.

Also, with the boy girl paradox is also asked with the same, at least one, not specifying which one is a girl. Which gives the same answer. Cause this is of course the same thing.

https://en.m.wikipedia.org/wiki/Boy_or_Girl_paradox

This explains everything, and if you actually read it you will understand and stop arguing, and you will understand why these threads are such good bate.

>>719986648
Samenewfag detected

Scum

>>719986820
>10
?????

>>719986931
Already fixed it faggot.
>>719986926

>>719986813
It doesn't matter, what the example is it could be two people painting fucking doors at random red or white and what's the chance they both get painted red

Door one red door two white
Door one white door two red
Door one red door two red

Can't take away variable probability because you have autism

>>719982742
Given 1 = heads

then there is 50% chance other will be heads too.

1/2

>>719982742
xx,xy,yy,yx xx,yx,yy,yx
2/8

>>719986910
>(.5*.5)/.5 = .5
YES??

>>719986627
You are assuming that the order of which one is heads or tails is relevant.

You have two coins.
You flip them both at once.
You know for a fact that one will be heads.
Doesn't matter which one.
It's not a 1/3 chance because the order doesn't matter and double tails is impossible.
It's a 1/2 chance.
It's just a coin flip.
You could already have a heads there and flip another coin and it would still be a 50/50.

>>719984099

Lol right rule, wrong application.

Probability of both heads- 0.25

Probability of "first" coin heads- 0.5

So 0.5

>>719986975
Fucking read you dense mother fucker.

>>719982742
50%

past events do not effect the future events. Any other answer fell for the gamblers fallacy.

>>719986926
Okay I'm done being trolled you can't possibly be this dumb right? I spelled it out for you like twenty times


See >>719986986
>>719986720
>>719986291

Your mother and father are brother and sister correct? Or best b8 ever

>>719987022
no because xy and yx are the same combination
double i

>>719986986
>My new neighbours have 2 kids
>While walking my dog I see 1 girl playing on their porch.
>My mom asks me about the new neighbours and if they have any kids
>I say yes they have 2 kids, I know at least 1 of them is a girl, havent seen the other one yet.
>She asks what are the odds they are both girls.
>I say 1/2 because I'm not retarded.

It's that simple. I havent seen the kid. He could be eithe ra boy or girl. 50/50 chance nigger.

post bait pleas

>>719987149
yes

>>719987149
Again you've seen the child first you we Todd, you're adding words and scenarios not in the original problem. Jesus Christ our world is done for.

Hurrr durrr coin is flipped and is 50% heads chance that means if I flip 100 coins I have just a good of chance that they all heads

Try it you tard good luck ever getting that to happen

1/2 if flipped separately. 1/3 if flipped at the same time.

Fucking retards

>>719987348
Finally a non retard arises

>>719987113
You're just repeating the same thing over and over again, except replacing coins with genders and paint colors.

>HUURR DURR I EXPLAINED IT 5 TIMES

You will make a great parent. Just repating it 5 times =/= proving your point.

You're just retarded and you are bad at math.

>>719987149
>>719987225
No. You saw either the oldest or youngest. You know that a specific one is a girl. This has been posted multiple times and if you understand any basic probability theroy, and if you actually read it, you should understand.

https://en.m.wikipedia.org/wiki/Boy_or_Girl_paradox

>>719987325
>Hurrr durrr coin is flipped and is 50% heads chance that means if I flip 100 coins I have just a good of chance that they all heads

That's precisely my point, each coinflip has an independent 50% chance, it's not affected by previous flips. It's not like after 10 heads the chance of getting a tails has increased. It's still 50%.

I know it's not intuitive but you have to think outside of the box.

>>719987405 see
>>719987348
You are repeating a bad logistical explanation and praying it will be correct because your brain doesn't understand the variable in the equation. Tell me you don't work with numbers or your brain or other people.

And yes I repeated it in the hopes you could see it doesn't matter if it's children, paint or fucking coins it's the same issue you inbred moron

>>719987348
why do you even have to flip the other coin if both sides of that coin are heads?

it's always 50% given the fact the coin has two possible but equal outcomes.

>>719987528
Exactly, flipped sepertely you fucking nigger!!!! The problem never says they are or in what order! Jesus fucking Christ you people are dumb

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>>719987529
Not the same person so I didnt repeat shit.

You're simply outnumbered because not everyone is dumb as you.

>>719987600
Then two of you are retards and if you'd like me to link the other 400 people saying the same thing as me I can so you can see how dumb you both are

>>719987533
Just shut the fuck up and go read some books

>>719987348
Not entirely true. If you flip one coin after the other then if the first is tails the second will be heads no matter what the first throw was 1/2 and the second was 1/1. But if you land a heads first it could be a geads or tails next which makes both the throws a 1/2 chance.

Throwing them both at once simplifies it because one will land heads, doesn't matter which. Then it's just a 50/50 as to what the other will land.

>>719987665
Trump is your president now. Time to start accepting logic.

>>719987594
If I flip 2 coins, and the first is a heads, the chance of both getting heads is 50% right? That we agree upon.

Now if I flip 2 coins, and coin number 2 is heads, the chance of coin number 1 getting heads is also 50%. The order doesn't matter, so it doesnt matter if it's stated in which order they are.

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>>719987643
If all you 1/3 fags are so smart, why are you falling for obvious bait?

>>719987692
You're forgetting they are two seperate coins with different probabilities

See:
>>719986291

>>719987453
Age doesn't factor in to that person's comment so it is correct. Dont be a shitter.

>>719987700
See>>719987781

>>719987747
>I was only pretending to be retarded

>>719987700
You're implying one establishes itself as heads before the other (just as in the other scenario), when the premise is that they land at the same time.

In which case, either heads/tails, tails/tails or heads/heads is the outcome. 1/3

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>>719987836
WTF man, you were only pretending? So all of us have been trying to convince you that the solution is 50% even though you knew all along?

What's wrong with you, filthy basement dwelling cunt. HURR DURR I WASTED UR TIMEZ. EPIC TROLLERZ

>>719987938
>You claim they fall in an order
>But really they all land at the same time

If I throw 1 coin 100 times, i will get heads about 50 times. If I throw 100 coins at once, there will still be 50 heads. It really doesn't make a difference kid.

>>719987982
>Not understanding green text or Harrible bait

Granted math experts have proven its .33% and the autists of /b were not going to get it correct... there were explanations for those who actually did think it was 50%

>>719987781
In what way does it show I said this?

By the facts given in the image, if I flip one coin first, that coin is a 50/50. If it is tails then we know by what the image tells us that one of the coins is heads so we know the next coin is heads. If you start again with the 50/50 coin flip and it lands heads then that coin could be the definite heads or the chance heads so the next flip is still a 50/50.

The only time the probability changes is when we 100% know what the next coin is in the case of a tails.

>>719988044
2/10 B8

>>719987808
The scenario described in that comment is not the scenario in the question being asked. The answers are not the same. Age doesn't factor in directly, but the fact that you know that a specific child is a girl does. Saying oldest/youngest is just an easy way of taking about it.

>>719988064
>Granted math experts have proven its .33%
Yeah and 95% of all statistics are pulled out of someones ass.

Even if it was bait, it's clearly not 'Harrible' if you're taking it. That's the whole point of bait.

You're like a fucking fish who got hooked, and then said 'Ha! Your bait tasted like shit!'. Well, then why did you fucking go for it, dumbass? Now you end up in the frying pan.

>>719988088
Again, you are adding the word first.

No one is disagreeing that if you flip one coin at a time it's fucking 50%

Here you go buddy, try and keep up http://www.math-only-math.com/probability-of-tossing-two-coins.html

>>719988197
>ha ha I only had nothing better to do as well! Successful bait.

Wew lad

>>719988162
I still don't see your point. If he knew there were two children and one was a girl there was a 50/50 chance as to what the second child's gender was...

unless your a tumblrina.

>>719988300
>>719988212

>>719988162
Ok, so if SOMEONE ELSE saw the girl on that porch, and told me as a third party: 'At least one of the kids is a girl', then my answer would suddenly be changed?

I'd still be faced with the same info and the same solution.

>>719988212
In my first comment I did point out the situation where both are being thrown at once but I didn't see where I could be showing that the coins didnt have the same probability.

>>719988300
Read this
>>719987453
The wiki article on the boy girl paradox explains things far better than anyone here will.

>>719988384
>>719988325

>>719988410
Hopefully that link will help you, if not you aren't cut out for math

>>719988260
I said it's NOT bait, dumbass. The answer is 50% and I stand by that.

I only said that IF it were bait, it would evidently not be horrible because it worked. It served it's purpose, which is to hook a fish.

Don't come to me with that 'You had nothing better to do?' bullshit, you are wasting an equal amount of time, just behind a different computer screen faggot. I'll spend my free time the way I want to.

>>719984314
>>719984359

How would Monthy Hall make it 50%?

The coinflip is not Monthy Hall imho.

To illustrate, making the coinflip-problem a Monthy Hall you would say sth like this:
You flip 2 coins. You catch 1 coin in mid-air and place it with Heads on the table. How big is the chance that both are Heads?
Then, yes, the result would be 50%

But in our coinflip problem, it doesn't state that a specific coin is placed as heads, but only 1 of them, which means that HT adn TH are two seperate outcomes and thus HH is a 1/3 chance.

>>719982742
> Maths PhD, have taught probability & stats at uni level
1/3

There are 3 possibilities where at least 1 is heads: HT, TH, HH. Only the last one is both heads, so 1/3.

>>719988560
See>>719988212
If you can't comprehend then math isn't your thing

>>719988585
TH and HT are the same combination and should be considered as such.

>>719988585
The wiki states 87 of MIT graduates got it wrong, saying you have taught probability doesn't mean shit, this is a question that goes against your intuition.

Read the rest of the thread to realize why you are wrong.

>>719988585
Everyone knows we're just fucking trolling dood

>thinking anyone on 4chan is that retarded to really think 50%

Don't need a phd

>>719982742

There are four outcomes when you flip two coins :

H-T
H-H
T-H
T-T

Three of these are included in the general statement "one is heads". There is only one outcome when it is two heads.

1/3 chance.

>>719988384
Yup. It would change. That's why this is such a hot topic, it goes against your intuition. If you really want to learn about it it's pretty fucking fascinating and the wiki article on it is a pretty good ready, which had been posted multiple times. If you just want to be an argumentative faggot then that's cool too.

>>719988771
/thread

>>719988710
OP here, I think you'd be suprised.

I've been defending 1/2 to rile people up, but that only amounts to 5% of the 1/2 people, they can't all be trolling.

>>719987060
thats the right answer since the probability of (first coin head) under the assumption (second coind head) is Pa(b) = P(a and b)/P(a) where P(a and b) is 0.5*0.5 and P(a) equals 0.5

>>719988808
No one is that dumb and I highly doubt you're OP. I've also been b8ing at the 50% answer

>>719988885
He's absolutely right!
>this guy is retarded

>>719988703
No, they are different, and must be regarded as different.

4 combinations
HH <-- only this one is both heads
HT <-- has at least one head
TH <-- has at least one head
TT <-- not included, no heads

=> 1/3

These fags are correct, it is 1/3.

>>719982799
>>719982906
>>719983296
>>719983334
>>719983415
>>719983929
>>719984099
>>719984196
>>719985934
>>719986015
>>719986114
>>719986614
>>719986820
>>719987348
>>719987938
>>719988064

If you have a red coin and a blue coin, there is a 1/3 chance you will get a scenario in which both red and blue are heads;

Both are tails (DISQUALIFIED)
Red is heads but blue is tails (ACCEPTED)
Red is tails but blue is heads (ACCEPTED)
Red and blue are heads (ACCEPTED)

You can argue this all you want but you'll look like a retard - it is proven mathematics supported by statistics, formulas, experts and computer simulations.

>>719988888
dude

>>719988888
wasted quints, fucking cunt, kys

>>719988888
QUINTS

>>719988888
you stole our penta

>>719988888

It's a quints

>>719982742
Are we tossing EUR as shown in the picture?

Given how many niggers there are in the world, there's a high probability there's one in the vicinity when you're doing the coin flip. Since he's a nigger he's about to steal your money so the answer is zero

>>719989021
"at least one of them landed heads"
well, IF the one WAS already flipped there is a 1/2 chance, otherwise a 1/3

>>719989062
Oh noooooo not your precious numbers!

>>719989180
also depending on the coins and the room there are tiny deviations on how likely it is to land on heads

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>>719986389
Rlly nigga?
The thing is... Did he at he say any moment that the FIRST coin will be head? just use ur brain...

>>719989316
Also what if it lands on its side!!

>>719989180
I don't know what you are quoting but I didn't say that one of them had already been flipped.

>>719988888
Why would I falsely claim to be OP? It's not like I'll get any credit for wasting my own and everyones time.

Not having a hissy fit that you don't believe me, genuinely interested in finding out what kind of value you think I'd get out of taking thread credit.

I actually started advocating 1/3 because the first posters all went for 1/2, then I switched later for shits and giggles.

>>719982742
50% always no matter how many times

>>719989345
No im not pretending
It says one landed on heads

Let me change my example to prove my point to show you.

Mr retard is buying two automobiles a Segway and bus are his choices

He is def! Getting one Segway at least

What's the chances he gets two ..obviously 50%

>>719989475
Ha ha! Touché!

>>719989516
/Thread

>>719988888
wasted

>>719989516
Hmm not bad trolling there

first of all they are euros
so if you flip two you end up with one
that means heads when at least one is heads is a 100% probability

H H
H T
T H

The chance of getting at least 1 coin being head is 100%
The chence of the other coin being head is 50%
Answer 50%

>>719989516
He might buy:
Segway and a Segway
Bus and a Segway
Segway and a Bus
1/3 broh...

>>719989875
No dood he already has one so second choice is just either bus or Segway 50%

Doesn't matter because the moment they land I'm going to put them both in my pocket and I will be 50 cents richer and will use it to make my own luck. I could dial a payphone I could take the subway, who fuckin' knows.

Actual answer from a Mathematician if anyone is interested:

P(H) = 1/2 = 50%
P(HH) = 1/2 x 1/2 = 1/4 = 25%

>>719989940
The thing is... he can buy in different orders, different options. Car 1 and Car 2 are two different things

>>719989426
>I don't know what you are quoting
OPs pic

>>719986627
>>719990182
OP here, winrar

>>719990221
Don't matter what order he buy it in it's his choice

>>719990182
Bait isn't even trying anymore. Thread is dead.

>>719989940
The question isn't "A nickel was flipped and landed heads, what is the probability that a quarter would also land heads"

It's more along the lines of "you flip a nickel and quarter and try to guess what they are, but your retard friend blurts out "we got heads!" before you cut him off. What is the chance that they're both heads?

Quarter tails + nickel tails = No
Quarter heads + nickel heads = Possibly
Quarter heads + nickel tails = Possibly
Quarter tails + nickel heads = Possibly

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>>719990282
Idiot it's 1/4

>>719990279
It does matter since we are talking about the options that the car 1 may be a bus or a segway or car 2 may be a bus or a segway.

>>719990408
You missed out, just go to bed.

>>719990349
this. pretending the first coin was already flipped is basically saying "what is the probably a coin would land heads" which is not the question. there are two coins and a specific result you are trying to achieve.

>>719990458
It's 1/4 i'm a mathematician

>>719990651
i'm a quantum physicist and you're both right and wrong

>>719990791
kek

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>>719982742
The awnser is 1/3 ya goofs.

If it said the first coin lands on head, then it would be 50/50 on the 2nd coin only; but it says at least one of them meaning the first H T and T H both count as a possibility.

It's confusing and really depends on how the question is formulated.

75% or 2/3, phaggot

>>719991173
3/4*

>>719991260
6/11*

>>719982742
>heads
>euro
pick one

>>719990975
Says BOTH landed on heads, are you R E T A R D E D? HT and TH are NOT possibilities

>>719991445
>being this mad and still objectively wrong

>>719991415
Many euros have actual graphics of a head on the other side, dumbass.

87/113

Retarded autistic low IQ neckbeards in this thread.

50/50 chance of any single throw being Heads or Tails. HEADS-HEADS would be 1/2 x 1/2 = 1/4 = 25% probability.

Close this thread.

>>719991765
Wow that's a great insight into the question "What is the probably a coin will land on heads" too bad that wasn't the question faggot

>>719991765
Reread the post.

>>719982742
do your own homework loser.

1/3 /b/ros

>>719991445
wow. go back to school man.

>>719983369
33.(3)/66.(6)=1/2

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>>719988888
fucking hell man

Are you looking for the answer that a professor wants, or the answer an engineer will give?

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>>719991765
Learn how to read nigga...
T and T its not an option...

>>719991946
>>719991548
>>719991901

"Both landed HEADS". What are you not understanding? HH is the only outcome that fulfils this criteria and the other outcomes have no impact on the probability of that outcome. The final answer stands at 1/4 or 25%. Case closed stop trolling.

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>>719991445
Alright, I'll explain it in dumbass speech.

There are 3 possible outcomes. We know that 1 coins, lands on head; we dont know which one.

Tails Tails(Not Possible)
Tails Head(Possibility)
Heads Tails(Possibility)
Heads Heads(Possibility)

Knowing that one lands on heads, means the 1st or 2nd coin can land on heads.

There is a 1 in 3 chance of getting heads heads. What most people get wrong is they assume the first coins lands on head, if that was true, it would indeed be 50/50 as the following would apply

Tails Tails(Not Possible)
Tails Head(Not Possible)
Heads Tails(Possibility)
Heads Heads(Possibility)

However the question states "one of them" which states that it can be both that land on heads and the 2nd has chance.

I hope this is clear enough to understand.

>>719992377
See:
>>719989021

>>719992377
Wrong, it's 1/3 dumbass. Tails Tails is impossible as one ALWAYS lands on heads.

Since it doesnt specify WHAT coin is gonna land heads AND it also just asks for the possibility of BOTH landing heads, it's a fucking coin flip.

Simple as that.

>>719992377
>implying tails tails is a probability

go back to school anon.

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>>719992452
Damn Thanks!!!!
Its like trying to teach a monkey, damn.....

1/4 cause theres 4 options it could land on.

>>719992791
Monkeys actually understand this pretty well. I'm surprised /b/ is dumber than monkeys.

Nah actually im not surprised.

>>719992857
No, there aren't. If one of the coins is heads, we know that tails-tails isn't one of the possibilities.

Honestly, this is closer in logic than the 1/2 people though.

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>>719992966
1/4 is way dumber tbh.

If you know one coin lands on heads and still think tails tails is possible, you're pretty fucking dumb.

The 1/2 people got tricked into thinking the 1st coin lands on heads, which makes 1/2 true. 1/2 people are stupid for not reading and understanding, while 1/4 people are just dumb in general

Simple python code that proves the answer is 50%

import random
c = 0
r = 1000000
for i in range(r):
if random.randint(0,1) == 1:
h1 = random.randint(0,1)
h2 = 1
else:
h1 = 1
h2 = random.randint(0,1)
if h1 == 1 and h2 == 1:
c +=1
p = c/r
print(p)

p comes out to approximately 0.50 bitches

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>>719993063
Just run into traffic, this bait is too obvious.

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>>719982742
30%

>>719992452
Jesus you're dumb.

"what is the probability that BOTH landed on heads"

= H + H = 1/4 = 50%

Why are you even talking about Heads + Tails as a possibility as that isn't BOTH heads is it? GO BACK TO school

>>719993128
Why the fuck make it that complicated?

>>719986015
There is NO possibility of having 2 tails since it's guaranteed that atleast one coin will be heads you turd

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>>719993157
"1/4 = 50%" just KYS mate...

>>719982742
It's just 1/2 * 1/2. A 50% probability for each event, and the outcomes are independent. So there's a 1/4 or 25% chance that they'll both land on heads.

>>719993193
because that is the formula for when something happens (A) after some other specific thing (B) has happened.

I just flipped 2 coins 10 times and it comes out at about half the time as H+H so thats about 50%

>>719982993
You don't understand the question. Pay attention to the "given" part.

>>719993339
not big enough sample size.

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>>719993157
I hope you're trolling at this point. That is not how probability works you degenerate fuck.

Let me demonstrate how fucking stupid you are. When you say 1/4 you are implying that T+T is a possibility, while you know that one coin will land on heads.

Fucking educate yourself on probability and stop sounding like a brain-dead monkey. It's very clear you have no idea what you're talking about and never studied anything remotely similar.

The answer remains 1/3 as T+T is never a possibility in this equation, no mather how you formulate this question; your logic is flawed.

>>719993336
It's really not that complicated tbh, you just eliminate that possibility of tails tails, which makes it 1/3.

If it was a complicated qeustion sure, but this was easy.

It's 50% you stupid fucking idiots. You ignore one coin because it has a 100% chance of landing on heads. So you're left with one coin that has a 50% chance of landing on heads.

>>719993128
Those who actually think that it is not 1/3 won't be swayed by this. They are like flat earthers, they gotta see it with their own eyes, anything else is just lies.

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>>719993063
Need to screenshot to get indentation in.
Surely simulating 1,000,000 flips is to everyone's satisfaction.

>>719993531
just wanted to make it perfectly clear for all the dummies

>>719993537
You dont ignore 1 coin, because you dont know which coin lands on heads you dumb dumb.

SEE

>>719992452

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>>719993595
Impossible man, I tried.

People who believe it's 1/4 or 1/2 are like muslims. No matter howmuch logic you throw at them, they'll be retards at the end.

>>719982742
Is this just a thread for fagmaticians to troll each other? Math is for idiots anyways, we don't even need math anymore. It's pretty much a useless pass time now that we have computers.

>>719993157

The equation is x/y. Let's start with solving x.

>"what is the probability that BOTH landed on heads"

Let's take a look. Whether you agree with 1/3, 1/4 or 1/2 we all agree only one of the possible flips results in heads/heads, so x = 1.

1/y

Now let's solve for y, knowing that one coin is heads (not knowing which coin).

Is tails/tails a possibility? No. Is heads/tails a possibility? Yes. Is tails/heads a possibility? Yes. Is heads/heads a possibility? So there are 3 possibilities. y=3

1/3

Using an example from an anon earlier, you are thinking of it in terms of "If I flip a quarter and it is heads, what is the probability that flipping a nickel will also result in heads?", which is ultimately asking "If I flip a coin, will it land on heads or tails?"

Think of it like this: You flipped a quarter and a nickel at the same time, with the intention of guessing what it landed on. Your friend covers the coins, but peeks and accidentally blurts out "one of them is heads."

Knowing they aren't both tails, what are our possibilities?

The quarter is heads but the nickel is tails
The nickel is heads but the quarter is tails
Both are heads

Understand?

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The path on the far right is not being included in the calculation, because it doesn't qualify for it, as there is no "heads" on that path

>>719992124
^

>>719993674

I hope the European race war comes to my country soon

As the question is asked 1/3

However, its sort of a trick question made to get wrong answers from people because they assume they know which of them landed heads and from people who have never done calculations with propability.
Propability is very counter intuitive, the answer is 1/3 and if you disagree you dont know what you are talking about and are making yourself look stupid.

that whole 00 01 10 11 thing is pointless, as we already KNOW that at least one of them is heads, so the other coin will decide the endresult (50:50)

>>719988885
no the question asks what the P(H|H) is. This equates to P(Heads and not tails)/P(H) which is 0.25/0.75 = 1/3. not sure if retarded or bait

>>719994115
The error is that you are assuming we know WHICH coin is heads. In probability, yes it absolutely matters.

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>Almost 300 posts
Holy fuck I wish I could believe it's just trolls trolling trolls.

>>719994115
10 and 01 are still 2 different scenarios, 2/3 of the time in this case, well done making yourself look stupid.

>>719994025
this

/thread

>>719994222

>Holy fuck I wish I could believe it's just trips trips trips. XD

>>719994333

>>719994176
it doesnt matter, as they are the same
if a is already head b will decide
if b is already head a will decide

>>719994025

why does it matter which one has already been decided? They're both the same, two-sided coin. Therefore, if we KNOW the outcome of one coin (doesn't matter heads or tails, just that we KNOW which it is), the other coin has a 50/50 chance of matching that fucking coin. Fuck you.

The answer is 1/3
There is however 50% chance after you've thrown the first coin.
I solved it now stop replying.

>>719994222

>>719994333

>>719994327
>gives 2 different options
>tells us they are the same

Get out of the genepool thanks.

>>719994224
you are assuming that both coins can be 0 (or "both coins could be tail") which is not possible. In order to 00 not happening one must already be set 1

>>719994327
If you flip a dime and a penny you get to keep whatever lands on heads, you can't say that a penny landing on heads and a dime landing on heads are the same thing.

Choose to believe it or not, 1/3 is a proven fact supported by algorithms, experts, tests and formulas. You're not doing your intelligence any favors arguing against it.

50/50 they are two separate entities, so if one lands on heads it doesn't effect the outcome of the other coin

>>719994419
its NOT possible that both coins can be random, because that would mean that 00 is possible, which it isnt

>>719994354
>just that we KNOW which it is
no we DONT and that is why you are stupid. We know that ONE of the coins is heads not WHICH of the coins is heads, you dont understand propability and just made yourself look very stupid.

These fucking underage faggots get out of my /b/.

>>719982742
1/3 and if you don't agree you are a retard.

fight me

>>719994531

retarded bait

It's much easier to think of the question as this:

- If I throw two coins into the air, what's the chance both of them will land heads?

And then ask this:

- If I throw two coins into the air, what's the chance at least one of them will land heads?

And finally:

- If I throw two coins into the air, what's the chance both will land heads, assuming it is impossible both land tails?

>>719994459
If you place a coin with heads up on the table and flip another coin that is the same it will be roughly 50% of the time heads. If you place the second coin heads up now and repeat the flips it will be roughly the same result. In what world does this mean 1/3.

>>719994354
You're equating

"We know one of these coins will be HEADS"

with

"We know THIS coin will be HEADS"

Knowing what one of the outcomes will be doesn't mean we know which one of the outcomes it will be which makes a difference in probability

>>719994616

>If I throw two coins into the air, what's the chance both will land heads, assuming it is impossible both land tails?

Fuck, here I should have said "assuming it is impossible both land tails simultaneously".

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>>719994594

>>719994459
The problem is, that this calculates how often 11( 1 in 4 cases) happens and puts it in relation to how often at least one is 1 (3 in 4 cases) , BUT OP said, that that 00 can not happen in the first place (so one must be already set)

>>719994694

I am that guy, and you are absolutely right. Learned something today and thanks for the explanation.

>>719994694
there is a 100% chance that one is 1

if the first coin is 1 there can only be 10 and 11

if the second coin is 2 there can only be 00 and 01

so no matter what, its only 2 possible cases

>>719994870
*if the second coin is 2 there can only be 01 and 11

sorry, my mistake

>>719994646
Because you are NOT placing a coin with heads facing up on the table. That is not what the question asked at all. You are flipping two coins at the same time, and by either someone telling you or the powers of clairvoyancy you know that ONE of them is heads but not which one.

You want all 11 cents. You flip a dime and a penny and resolve to keep whatever lands on heads. Your friend tells you ONE OF THEM lands on heads. What are the possibility you get to keep all 11 cents?

Penny is tails and dime is tails (0 cents but confirmed to not be an option)

Penny is heads and dime is tails (1 cent)

Penny is tails and dime is heads (10 cents)

Penny and dime are both heads (11 cents)

There a 1/3 chance you get your 11 cents.

>>719994694
It doesn't matter. Half the time, the first coin will be heads, half the time, the second coin will be heads. therefore, 100% of the time at least one will be heads. HT is exactly the same result as TH in the overall scheme of things.

>>719984232
Yes

>>719994957
*if the second coin is 1 there can only be 01 and 11

fuck my life

>>719994967
Different problem, in this case both coins are identical.

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>>719995091

stop

>>719994870

There's a 100% chance one is heads, indeed:

- Heads and Tails
- Tails and Heads
- Heads and Heads

Thus the probability is 33%.

>>719995128
It's an example, but it's not a false equivalence. You relying on the fact that the coins are identical is what's making you interpret heads/tails and tails/heads are the same option, when actual probability mathematically dictates there is a 1/3 chance.

>>719995128

No, they aren't. You think they are identical, but they are two separate instances.

You can't equate "Tails and Heads" to "Heads and Tails", that isn't how it works. They are separate entities.

Otherwise, the question may as well ask "I flip a coin, what's the chance it lands heads"?

>>719995158
no, only if its implied that 00 is a possiblility (aka both coins need to be flipped)
in that case 00 could theoreticly happen but would be ignored (3 in 4 chance of possible outcome) and because 11 is a 1/4 chance we would put them in relation (3/4)/(1/4)=0.(3)=33.(3)%

BUT 00 IS NOT POSSIBLE

>>719995379
*(1/4)/(3/4)=0.(3)=33.(3)%

>>719995330
>Otherwise, the question may as well ask "I flip a coin, what's the chance it lands heads"?

its supposed to be more complicated, so people would start using their brains

>>719995330
The order doesn't matter. HT is TH because when they land they can be rearranged to form one-another. Our only two options are (HT/TH) and (HH).

sure they can, but TH and HT are still 2/3 of the flips, you can test it you know, you have 2 coins dont you?

>>719995379

I don't quite understand what you are saying, so I'll just post the question and explain why 33% is the right answer.

>Two regular coins were flipped. What is the probability that both landed heads given that at least one of them landed heads?

When flipping two coins, there are four possible outcomes:

- Tails Tails
- Heads Tails
- Tails Heads
- Heads Heads

Here's the fundamental problem with a lot of people's understanding. They think the only valid answers are:

- Both land tails.
- Both land heads.
- One lands heads and the other lands tails.

Which is also true. It is a simplification of the possibilities I mentioned earlier. But "heads and tails" and "tails and heads" are two different scenarios. If there's a 50% chance a coin lands heads or tails, why would you group two coins together and say "H and T" is the same as "T and H"?

This is why some people like to make the comparison with two different coins, because then the solution is much more obvious.

>given that at least one of them landed heads
1/1 * 1/2
1/1 because it's 100% occurrence rate of one being heads; the other is 50/50

>>719995128
Penny and dime were merely my way of pointing out that heads/tails and tails/heads are different occurrences. We know that one coin is heads but not which one; even with identical coins, there are three equally likely scenarios when your friend uncovers the coins:

The first coin will be heads, the second coin will be tails.

The first coin will be tails, the second coin will be heads.

The first coin will be heads, the second coin will be heads.

>>719995628
this
its either
(Set / 0 or Set / 1)
or
(0 / Set or 1 / Set)

>>719995628
Why would the order not matter? There is an equal chance that the final result will be heads/tails, tails/heads or heads/heads. If you combine the two seemingly "identical" options, they still account for 66% of the possibly outcomes.