>>685163413
>at least one
either 50% or 100%, depending on how many heads there were before.

>>685163626

What?

25%

1/3

Anyone who says 50% is either trolling or retarded.

75%

>>685163626
>>685164320
>>685164458

Wrong

SO what's the right answer? Can anyone explain? I'm shit at math.

>>685163413
>euro
Fuck off yuropoor

It has to be 50% right?

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>>685165402

>American triggered by math

>>685164996

Here's all the outcomes for flipping 2 coins:

HT
TH
HH
TT

2x Tails isn't a valid option cause were looking for at least 1 heads, that leaves 3 options. 2x Heads is one possibility from 3 options, so 33%

>>685163413
50%

Two coins flipped.
It is given one is always heads. The other is either heads or tails. Therefore, it's 50/50

>>685165613
TH or HT doesn't matter because the order doesn't matter.

>>685165943
but isn't it somehow more likely that there's one head and one tails than two heads

>>685165613
There is no difference between HT and TH in this case.. they are the same since one of the coins is always heads

>>685165943
>>685166048

3 ways to get at least 1 heads

HH
HT
TH

HH is 1 of those 3

1/3

>>685164365
This one, there are 3 case with one head, and one of those is two heads, so its 1/3, basic math.

>>685166177

Yes.

66.666....% HT/TH
33.333....% HH

1/3

>>685163413
0%
coins never land on heads

>>685163413

1/3

Google gambler's fallacy

Thinking that the other coin has any Influence next is stupid.

If one is head the the other is simply 50/50

If we assume one is head then the question becomes "what are the odds of a coin flip showing head"

Sixth form S1 is where its at

1/3 anyone who says otherwise is retarded

50%. if we can assume that there will always be one head then all we have to figure out is the possibility of the seconding being a head.

>>685166937
second*

The probs for a single coin are 50%. Four combinations for two coins, three of them show any head at all. That's a total of 150% for the question.

>>685166858
Go to school an learn statistical maths. Stupid person.

Ok stupid fucks listen up.

Two coins are flipped and one will deffinitly land on heads cause plot. What is the chance both the coins land on heads?

The first coin is already stated to land on heads. And there are only two possible outcomes left, the second coin lands on heads or tails and thats a 50/50 chance.

So considering one coin is gonna land on heads guaranteed the question becomes: what is the chances that this single coin lands on heads.

The answer is %50

>>685166858
>one is head for sure
>the other one is 50/50
>50/50 that both land heads

>>685166335
One lands heads always, the other one either lands heads or not, so its 50/50, there are no other cases since the question is just the chance of both landing on heads

>>685167155
>>685167188
doubles of truth

>>685166731

At least one is heads, so that leaves 3 possibilities

TH, HT or HH.
HT and TH are NOT the same.
Getting just 1 heads is lower chance as getting both heads. But if we split up TH and HT they are equal chance as HH.

>>685167155
it doesn't say the first coin, it says at least one coin. It could be either coin. There fore there's three possible out comes.

HT
TH
HH

so 33%

>>685167423
But that isn't the question. Reread it.

It's simply if one coin shows head. What are the odds of the 2nd one showing also heads. Never mentions any specific order.

>>685166937
This. End of discussion.

>>685163413
51%

Everyone who thinks its 50% should go back to school lol

>>685166219
As right as your reason Ling may sound...

HE
HT
TH

There is no difference between TH and HT.

So what we have left is...

HH
HT/TH

50% mate.

The first coin is given, heads. What's the statistics of a second, indipendant flip being heads... 50%

>>685163413
>posting ambiguously worded math questions

One of the coins is definitely heads, so we disregard that coin. It does not affect the outcome of the other coin.

So basically 50%.

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>>685166731
>>685166937
>>685167151
>>685167155
>>685167188
>>685167332
>>685167333

This is a basic conditional probability question and it does not contradict the Gambler's Fallacy.

Flip 2 regular coins. All possible outcomes are:

HH
HT
TH
TT

But we have a CONDITION; At least 1 coin landed heads.

There are 3 equally probable ways to get AT LEAST 1 heads coin from a 2 coin flip. These are

HH
HT
TH

Of those 3, ther is 1 case where both coins are heads

1/3

>>685167920

HT and TH are different.
If it didn't matter then just getting one heads is twice the chance of getting 2, but i don't see this addressed in your reasoning anywhere.

>>685167920
There is a difference between TH and HT, the question never says the first coin, it says at least one of them, could be either one.

It's fucking 50% you fuckin' mongols.

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>>685167920
>There is no difference between TH and HT.

Yes there is. They are 2 separate and equally probable permutations. This is basic probability, anon.

Think of it like this

Take two different coins. Let's say, a penny, and a quarter. Each coin has a 50% chance of landing either heads or tails. You flip both coins. What are the possible outcomes? Well, let's see:

penny = heads & quarter = heads
penny = heads & quarter = tails
penny = tails & quarter = heads
penny = tails & quarter = tails

4 possible outcomes. Each of them equally likely to occur (25% or 1/4)

Now, surely we can all see how the results,
penny = heads & quarter = tails
and
penny = tails & quarter = heads
are different, right? Surely you can see how these are two distinct, separate and equally probable outcomes, yes?

Answer is 1/3

>>685163413
627%

>>685168076

What's ambiguous about it?

>>685167577
HH and Ht are the same thing.
And no it doesnt specify which coin lands on heads, but that doesn't matter. The outcome of one coin doesn't affect the outcome of the other.

>>685168090
>One of the coins is definitely heads, so we disregard that coin.

Which coin?

>>685168223

Retard detected.

>>685168101
one coin lands heads, the other has a 50% chance of landing heads
HT/TH don't matter because the coins are identical and one WILL land heads without a specific order
i dont see whats so hard to understand, there are only 2 options

>>685163413
total 4 scenarios (2 x 2) - HH, HT, TH, TT. Knowing that one of them is heads we have HH, HT and TH left. Probability of HH is 33.(3)% or 1/3

>>685163413
Its 50%, anyone saying otherwise is wrong.

One if given, so you are only flipping one coin.

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>>685168572
>The outcome of one coin doesn't affect the outcome of the other.

We know. The answer is still 1/3.

Pic Related

>>685168101
Wrong.

HT and TH are the same outcome.

50/50

>>685168469
And if you were to take that one of them is always heads, let's say, penny is heads, that leaves you with qrt able to go heads or tails, 50%, and that is it for that coin toss, if we were to assume the quarter is heads, that's a whole another coin toss

> implying statistics knowledge makes you smart

Odds of first coin being the heads coin: 1:2.

Odds of the second coin being the heads coin: 1:2.

Odds of the first coin being heads if second coin is the heads coin: 1:2.

Odds of second coin being heads if the first coin is the heads coin: 1:2.

Combine the odds: 1:2 x 1:2 x 1:2 x 1:2 = 1:16

Here we see how the knowledge of the given heads coin robs the chances of the other coin being heads.

50%

>>685168572

That's like saying this:

What are the odds of getting 2 heads when flipping 2 coins:

TH/HT
TT
HH

So it's 33%?

No it's not, it's 25% because HT and TH are not the same. If you treat them the same you should weigh their odds at 50% since when flipping 2 coins getting 1 heads is 50% chance.

>>685168617
It doesn't matter.

>>685168617
the coins are identical, it does not matter
one coin is out because it lands heads
the other 50%

>>685168674
>one coin lands heads
but which one

this is why HT vs TH matters, because you're not told which coin turns up heads

98.31647%

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If you did it 100 times.
And you ignored all the results which didn't have at least one head.
Which fraction of the remainder would have both coins head?

>>685168774
fucking this, i dont think it could be explained easier for you retards

>>685168557
OP said at least one coin. Leading some people to believe that it is a specific coin that will always be heads and others to believe that it is unknown which coin is guaranteed heads. It makes all the difference.

>>685168922
Lol retard, there has to be one heads...

One has to land on heads. Which give you a 50% chance that the other will either land on head or the other will land on tails.

Keep in mind, the 1st coin is supposed to land on heads.

simple math kids.

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>>685168674
>HT/TH don't matter because the coins are identical

They are 2 separate coins.

HT and TH are 2 separate and equally probable permutations.

For a 2 coin flip, these are the possible outcomes (probabilities in parentheses):

HH (25%)
HT (25%)
TH (25%)
TT (25%)

Or if you prefer it this way

HH (25%)
HT/TH (50%)
TT (25%)

As at least 1 lands heads TT is eliminated.

Pic Related: Bayes Theorem

Answer is 1/3

>>685168922
Well actually you do get 25% chance for HH or TT and 50% for HT/TH, which is the same..

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It depends on the country. Irish 1 Euro coins don't have heads, thus 0% there.

>>685168101
Okay, this is true, but what if they were flipped chronologically? As in the one that landed heads was already flipped, and this is where the observer comes in. Now, this narrows it down to any option with H going first. HT and HH. TH and TT are impossible, not because the asker laid down a vague requirement, but because the "heads" hasn't been flipped like he said he has. Again this is all assuming that one was already flipped. I think that's where a lot of people got confused.

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>>685168774
>>685169245
>>685169176

For anyone who thinks the answer is 50%, answer the question in the pic. Now you see how you are wrong.

Answer is 1/3

>>685169073
if its two same coins there is no way of telling and it does not matter, if one HAS to land heads the other has a 50% chance of doing the same

http://math.stackexchange.com/questions/991060/flip-two-coins-if-at-least-one-is-heads-what-is-the-probability-of-both-being
Faggots

>>685169525
>if it's two same coins there is no way of telling
so someone puts two identical quarters on a table in front of you and you immediately go "HOW DO I KEEP TRACK OF THESE SEPARATELY, IT'S IMPOSSIBLE"

>>685169465
But if we knew WHICH coin would be guaranteed heads it would be 50%

That's what I was trying to explain.

>>685169257
It doesn't matter. You have assumed the question demands constraints on the order of outcomes.

In practical application the answer is 1/2.

>>685169688
obviously, but you don't

>>685163413
Do your own homework nigger.

>>685169465
TT - no
HT - possible
HH - possible
50%

>HT/TH is not relevant

>>685169612
>/b/
>stackexchange link
>o tempora, o mores

>>685163413
Oh it's this thread again. Needed to prove that your STEM degree was better than Gender Studies did you?

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>>685163413
zzz this question is bait. It's years old for trolling on /b/, its decades and decades old in general. The answer is 33%, trolls and idiots will say 50% and deny that when tossing the coins, TH and HT are two separate events.

https://en.wikipedia.org/wiki/Boy_or_Girl_paradox this question is a reformulation of this paradox.

>>685170090
why would that ever need proof

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>>685169328
>what if they were flipped chronologically?

They can be flipped simultaneously, sequentially or you could simply flip a single coin twice.

In all cases where at least 1 coin (or flip) lands heads, you will get both heads (or 2 heads) 1/3 of the time.

The answer is 1/3 in all cases.

> As in the one that landed heads was already flipped, and this is where the observer comes in.

If 1 coin is flipped and it is observed to be heads, then of course the probability that the next flip is heads is 50%, but this is NOT the case in the OP question.

>I think that's where a lot of people got confused.

I think you might be correct, along with the fact that probability is often counter intuitive for most people.

Pic Related: Answer is 1/3

>>685169939

TH is also possible

1/3

>>685169836
>In practical application the answer is 1/2.

Don't ever gamble, you numbskull.

>>685170095
It depends on how you interpret the question you dumb fuck.

It can't be a fair toss though because one coin must always be heads, so therefore the answer is 50%.

>>685169257
so you're basicaly saying the coin that is not forced to land on heads has a higher chance of landing tails than heads?

>>685169465
No. Because it was not stated in the OP, order does not matter. TT Won't happen, and both TH HT are the same. It is a 50/50.

>>685170095
> From all families with two children, one child is selected at random, and the sex of that child is specified to be a boy. This would yield an answer of 1/2

^From your wikipedia article

From all possible outcomes of the coin flips, one coin is selected at random, and the side of that coin in specified to be heads. This would yield an answer of 1/2

Congrats, you proved yourself wrong

>>685170586
Do you know which coin? Because if not then there's three possible configurations for the coins to land.

TH
HT
HH

all three are distinct and satisfy the requirements of at least one head. All three have the same chance of occuring.

If we knew which coin would be heads then there would only be two options.

HT
HH

and then you'd be right.

But we don't know which one, and you're wrong.

>>685170716

What? No.

No coin is FORCED to land heads.

2 regular coins were flipped, and at least 1 of them landed heads by chance. it could be either coin. This means that EITHER coin could STILL be tails, just not BOTH.

This leaves 3 equally probable outcomes in the sample space

Heads - Heads
Heads - Tails
Tails - Heads

1/3

why doesnt someone just flip two coins a fuckton of times and comes back with an answer.

>>685170897
>and both TH HT are the same.

Don't be fucking stupid and read this >>685168469

Answer is 1/3

>>685171147
The result is the same, one coin is out of the equation, not knowing which one it is doesn't change a single thing.

>>685170967
>read every second word of the article
>instantly declare yourself smarter than every mathematician on earth
kill yourself.

>>685171452
the result is not the same, why do you think it is?

>>685171452
>not knowing which one it is doesn't change a single thing.
yes it does

Running a simulation of the scenario in the OP 10,000,000 times I get the following results (1 is head and 0 is tails):

{ '10': 3750778, '11': 2501153, '00': 0, '01': 3748069 }

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>>685170967
oh look, people are cherry-picking parts of the article knowing that not many will click the link.

these threads get more and more predictable every time they get posted.

>post other communities who agree on 1/3
>"bandwagon"
>write a program to do the experiment
>"your program is flawed"
>someone posts the video of a live demonstration
>"he just cut out all the takes where it didn't work"
>post the Bayesian analysis
>9x anons faking their way through a refutation and ultimately ignoring the post

if you want to believe that the answer is 50% more power to you, but you're wrong and I hope you really are trolling and not just retarded.

>>685171594
I did not come to this conclusion on my own you know.

I got it from the article.

>throw both coins
>one lands heads the other lands heads with a probability of 50%
>50% that both land heads

>throw one coin, the second later
>first lands heads, second 50% chance for heads
>50% that both land heads

>throw one coin, the second later
>first has a 50% chance of landing heads, the other has to land heads
>50% that both land heads

how would anyone throw the coins to get 1/3 HH?

do your coins have an extra side?

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>>685171350
>why doesnt someone just flip two coins a fuckton of times and comes back with an answer.

Done

Pic Related: 1/3

ITT:
High school graduate mathematicians that does not understand that both 1/3 and 1/2 can be the right answer depending on how you interpret the fucking problem

>>685171814
>>685171965

like clockwork, the thread continues.

>>685171924

>this is b8

>>685171965
i said flip two coins, not make a program.

>>685171868
An article which you obviously misunderstood and copypasted from. And what's even more damning, right above that line you copypasted is this one

>From all families with two children, at least one of whom is a boy, a family is chosen at random. This would yield the answer of 1/3.

Just stop.

>>685171421
I'm not you fucking cunt, its not a permutation. It's a combination. Order does not fucking matter, it was never stated.

It can be a quarter or penny, all it asked was the chances of both landing on heads. Each coin has a 50/50 chance of being heads, and one is already given. You are only flipping the other one.

Stop being autistic.

P(A|B)= P(A and B) / P(A)

P(A and B) = .25

P(A) = .75 [HT, HH, TT, TH] 3/4

.25 / .75 = P(A|B)
Thus,
P(A|B) = 1/3

>>685171646
In order for the coin to be heads, the result was decided before either of the coins were tossed.

>>685172168
If you could understand what he has written in his program you would know that you have been proven wrong

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If one lands one heads 100% of the time the probability of both landing on heads is 50%

If the one landed on heads by chance it's 30%

This thread is either to fuck with authists or just bait.

>>685172037
you can interpret moby dick such that the whale is just a whale, but you'd still be considered an idiot by the general population.

>>685172168

Simulation is more time efficient. Does the same job as 100 million flips of 2 coins.

>>685172336
Let's see you interpreting my dick inside your ass

>>685172161
how is this bait? its common sense.
one heads, one regular cointoss
do you imply a coin is more likely to land tails than heads?

>>685172037

>muh interpretation

No. the answer is 1/3 to teh OP question. There is no ambiguity here like there is in the Boy Girl Paradox.

ITT: Retards trying to "prove" a paradox.

>>685172171

>From all families with two children, at least one of whom is a boy, a family is chosen at random. This would yield the answer of 1/3.

From all possible outcomes of the coin flips, at least one coin is heads, an outcome is chosen at random. This would yield an answer of 1/3

It was right under the one I got, I saw it. An outcome is not chosen at random, one coin is chosen at random.

>>685164365
how the fuck is it not 50%?
you are guaranteed one of them lands heads so that leaves one coin being flipped which makes it 50%

>>685172235
That's not what the OP says. All we have is a condition that at least one is heads, it never says which one.

>>685172432
>>685172231
Or you can just do some basic conditional probability.

50% if you don't care which of the two coins is heads and you are keeping it real.

33% if you want to be a nerd about it and pretend that flipping one coin first instead of the other, like, totally makes a difference.

>>685172604
Alright, I see where you're coming from.

With the vagueness of OP's question you can still answer it two ways though.

>>685172555
No it's not, that would mean that which coin is heads is pre specified, but the OP says nothing about that. All we know is that at least one will be heads, not which one.

>>685172587
read one of the lenghty explanations on here, such as
>>685170307

50% [email protected]

>>685172189
>it was never stated.
>2 coins are not 2 individual objects

Congratulations. You are retarded.

>>685166219
are you retarded? switching the TH and the HT to say those are 2 possibilities is fucking stupid

I would say 33%
we got 3 different outcomes
1:first flip heads second is not
2:first flip is a fail second is heads
3:first flip is heads second is also heads
not good at this but I think they all got the same chance to occure

>>685172835

>No it's not, that would mean that which coin is heads is pre specified

see

>one coin is chosen at random.

^This does not specify either coin

>if i throw two coins and one will be heads the chance of the other landing heads is 1/3
>if i throw one coin the chance of it landing heads is 1/3

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>>685172231
>>685172432
>>685172432
>>685172606

Yeah but chances are the 50% retards don't understand programming OR Bayes' Theorem, so it doesn't really matter.

hEY 50% fags, here's a pic with a VENN Diagram

Look

VENN DIAGRAM

Woooo woooooh can you say VENN diagram?

You're a big boy now.

Answer is 1/3, plebs.

>>685172322
Yeah people here are arguing about the question instead of the answer

>>685172899
large fries please

0%. You are flipping a coin over. Not tossing it. If one is already on heads then one can't magically stay heads when turned over.

>>685172769

You're actually a fucking idiot. Holy shit I hope you are trolling.

>>685172780
>With the vagueness of OP's question

What vagueness. It's a pretty common and basic conditional probability question.

alright, retards
one of the coins lands heads
the other is a regular coin with a normal chance of landing heads which is 50%
just because we don't know which is which does not mean one of the coins suddenly decides it wants to be the other, completely fucking up the probability
its 50% as stated in many posts
anyone saying its 1/3 is an autistic little faggot

>>685169253
>>685169253
>Keep in mind, the 1st coin is supposed to land on heads.

Where does it even say that?

There are 3 potential outcomes. Think this through before you open your mouth.

Outcome 1> First coin is Tails. Second Coin is Heads
Outcome 2> First Coin is Heads. Second Coin is Tails.
Outcome 3> First Coin is Heads. Second Coin is Heads.

Outcome 3 has 1/3 chance.

Now, if the question was WORDED differently>
For example. Two regular coins were flipped. What is the probability that both landed heads given that the first coin landed heads.
Now you have two options. which gives 1/2 chance

>>685173734
You have to observe the coin to know if it's heads generally.

>>685163413

since you've already told us that one of the two coins landed heads up, there is a 50% chance that the other coin will also land heads up, ergo the answer is 50%

>>685174094
nigga, if one HAS to land on tails
Outcome 1> First coin is Heads or Tails. Second Coin is Heads
Outcome 2> First Coin is Heads. Second Coin is Heads or Tails.

the one that does NOT land on heads will either land on heads OR tails

>>685173405
This. And to anyone that still doesn't understand that it is 1/3, actually try to actually flip a pair of coins 100 times (excluding any TT) and see that it is going to tend to 1/3.

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>>685173550

kek'd

>>685172899

They are 2 separate outcomes, Tyrone.

Think of it like this:

You're with your homeboy, Tre. You and Tre see this skinny ass white boy walking thru your hood like he lost or sumtin.

So u distract the cracka while ur homeboy pulls the ounce of weed out dat fools backpack

You both run away from the dumb cracker, but now Tre won't share the weed with u.

So

Tre got the weed
Tyrone got no weed

is not he same as

Tyrone got the weed
Tre got no weed

Understand now? No?

Ok I'll get a large Coke with that, thanks.

Answer is 1/3

1/3

>>685173637
Alright, cool dude. Come sit with me and have a beer. Now put a quarter on the table with its heads face up. Now tell me there's a 33% chance that the coin you're going to flip now will be heads. I'll pick tails so we can have a friendly bet, see who pays the bill.

I think you are under the impression that somehow, the 33% possibility has any tangibility in the real world. It's just wind. Sure, mathematically it stands, but in practice, the rules change. Don't call me a fucking idiot because you are an autistic nerd who's never touched a titty in his life, son.

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>Matlab fag here
Ran a matlab simulation with 10000 throws of 2 coins. These are the probabilities of either getting 0, 1 or 2 heads.
Since we know one of the coin is heads, 0 heads is excluded.

Thus, normalizing the chances of getting 1 head or 2 heads back to one (chances have to add up to 100%)

P(X = 1) = 0.50/(0.50+0.25) = 66%
P(X = 2) = 0.25/(0.50+0.25) = 33%

Chance of getting 2 heads is 33% if one of the two coins is heads. No theoretical proof was used, real practice (in matlab) says it is 33%, just like the theoretical proof does.

>>685174391
You listed 4 outcomes there you dumbfuck. The clue is when you have to use the word OR, twice.

>>685174145
>You have to observe the coin to know if it's heads generally.

You are told in the question. you don't have to observe shit.

>>685174604
Underrated post

>>685174391

>OR
>counts this as 1 outcome

JESUS fuck this better be b8

>>685174730
i listed two outcomes, in both the chance is 50% for two heads, you are the dumbfuck for thinking math solves all your problems

>>685174287
>one of the two coins landed heads up

Which coin?

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>>685174604
top kek

>>685174949
I'm not a baiter like most people on b
but if you really think its 33%, boi you never threw a coin did you?

>>685170307

ok, i challenge you to prove it with observation:

1) get two nickels
2) pick either nickel and lay it on the table with heads showing
3) flip the other nickel 100 times.

if you get heads only 33 times (33%) then you are correct and us 50% fags were wrong.

but when you get heads roughly half the time, you'll see us 50% fags were right

/thread

>>685175015
the one that lands heads up
the other is the 50% chance of another heads

>>685174604
>Now put a quarter on the table with its heads face up.

You're "fixing" a coin as heads.

The OP question does not "fix" any coin.

In the OP question, EITHER coin could STILL be tails, just not BOTH.

In your scenario, one specific coin CANNOT be tails.

That's the difference.

Answer to your scenario is 50%.

Answer to OP question is 33%

>>685175413
that's not how chance works you fuck

>>685170307
problem is that people think (me included) that 2nd and 4th situation in ur pic are the same.

>>685174604

>math doesn't apply to the real world

Please don't procreate.

>>685165402
that currency is still worth more than a USD man...

Were they flipped both at the same time or one after the other?
Same time = 1/3
Heads first = 1/2

>>685175413
>>685174604
this, nerds. i think you got beat up in school too much and have brain damage now.
33%, thats the chance my sides stay on orbit after i'm done reading wannabe-einstein posts

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The OP question makes no distinction between which coin lands on heads. All it says is "given that one of them lands on heads" means that the only variable is the unclipped coin.

1/3 fags have to add new info to the question to distinguish between coin 1 and coin 2 being the predetermined heads-only coin.

This would be fine if we were sitting in a statistics class that was covering the concept, so the extra info would be implied. But we're not in that class, the info wasn't implied or provided, so you have to add it which changes the question.

Answer: 50%. Stop trying to be clever, 33% fags. You're bad at this.

>>685175727
Actually it doesn't even need to be heads first.

>>685175015

it doesn't matter which coin

when one coin lands heads up, what are the odds that the other coin will land heads up?

well, since the odds of the other coin landing heads up is 50%, the answer is 50%

see >>685175413

>>685175616
Don't force your way of life onto me, nerd

>>685175529
>that's not how chance works you fuck
so, if i throw a coin it does not have a 50% chance to land heads?

>>685175426
>the one that lands heads up

Yeah, which coin is that?

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>>685175767
This one's to you, friend

>>685176037
IT DOES NOT FUCKING MATTER
one lands heads, no matter what
the other can land heads or tails

there is no need to ask 'which one?'

>>685175413
>2) pick either nickel and lay it on the table with heads showing

I don't understand how so many of you get this so badly wrong.

That is NOT what happens in the OP question.

in the OP question, no coin is FIXED.

so you can't FIX a coin by laying it heads up on the table and pretending that youy flipped it, you fucking simpletons.

Jesus Christ.

Answer this question:

2 regular coins were flipped. Tails -Tails is NOT the outcome. What is the probability that BOTH coins landed heads?

>>685176469
50%

1:2
this is for retards?

>>685175571
>problem is that people think (me included) that 2nd and 4th situation in ur pic are the same.

They are NOT the same. See >>685168469
for explanantion.

1/3

>>685176469

it's 50%

either both will be heads, or only 1 will be heads

50/50 shot

>>685175860
>it doesn't matter which coin

It does when EITHER coin could be tails, just not both.

Gives 3 equally probable outcomes

Heads - Heads
Heads - Tails
Tails - Heads

1/3

>>685163413
This isn't a well defined problem.

There are 2 scenarios here:

scenario 1:
We toss them both and if neither are head, we do a toss again until at least one of them are head. In this case the chances of getting both heads is 1/3,

scenario 2:
We put down 1 coin on head and only toss the other one. In this case the chance is 1/2.

Both scenarios are valid because the problem isn't well defined enough.

>>685176469
50%

Either both land on heads or one of them doesnt.

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>>685175780
Someone get this man a beer!

>>685176403

But how do you know which 1 is heads then?

Is it HT or TH or HH?

3 possibilities

33%

>>685176996
>>685177105


2 ways to get a tails
1 way to get both heads

1/3

>>685174532
Tyrone and Tre are distinguishable, they are different in many ways. Two coins are not so distinguishable, they are alike in many ways.

ITT: 33% faggots try to make reasonable people that the fixed result of one coin does not equate to flipping one single coin.

Just give it up already. We see how you could be right in theory. It just isn't the case for people who don't have the patience for this nonsense.

>>685164365
No no no this is probability. There's no guarantee it'll be heads so the probability stays the same, always. If I flip it 100 times and it landed on heads each time what's the probability of it landing on tails the next time?

im publicly educated

>>685177034

but knowing that one coin is heads means we only have to worry about the other coin

it doesn't matter if "the other coin" is coin A or coin B

we know that when coin A is unknown, coin B is heads, so there is a 50% chance of coin A flipping heads

and we know that when coin A is heads, and coin B is unknown, we know that coin B has a 50% chance of flipping heads

so you keep acting like we have to worry about both coins, but we don't - your TH/HT bullshit gets in the way of you seeing reality

reality is, if you flip two coins, and one of them will always land showing heads, there is a 50% chance that the other coin will land showing heads

it's really that simple

now get back to /soc/ and see if a girl will write your name on her tits so you can fap

>>685174986
NO you fucking faggot
Example:
Your outcome 1: first head/tails
If tails und then other coin must be Head
If Head it is head/tails with the second coin

How fucking dumb are you?

>>685177168
But how do you know which 1 is heads then?
you throw them, you see the result.
one will be heads or both will be

>>685177168
If we know that one of the coins is heads, then we must have already flipped at least one of the coins. Or even if a magician did it, it's the same result.

I was wrong and misread, it's 1/3

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>>685175780

>The OP question makes no distinction between which coin lands on heads.

That's why the answer is 1/3.

Pic Related: 1/3 for OP question

Source: University of Washington Math and Stats Department
http://courses.cs.washington.edu/courses/cse312/11wi/slides/04cprob.pdf

>>685163413
33.3%

>>685177340

>2 separate objects are alike
>they must be the same object

50% fag logic

>>685177377
>nonsense.
>math

Large McChicken Meal, please.

>>685177464
>one is heads
>both are heads
50% chance for both to be heads
why are you confused?

>>685163413
It's 1/3...
I thought /b/tards were smart. I was wrong.

>>685177436

When you flip 2 coins, there are 4 equally probable outcomes.

HH
HT
TH
TT

3 of these satisfy the condition in the OP question.

1 of those 3 is HH

1/3

>>685177476
>But how do you know which 1 is heads then?

You don't.

1/3

I'm going to see if I can settle this, if you respond, please keep it short so I can reply really quickly, don't add any insults or anything, just keep the basics of your rebuttal.

This is directed at anyone who thinks it's 1/3 because there's three possible outcomes, and that TH and HT are distinguishable.

Say you have two four-sided dice, what is the probability both landed on one, given at least one of them landed on one.

It's 1/4, because possible outcomes are 1-1,1-2, 1-3, and 1-4.

By your logic, it would be 1/7, but it's not because the possible outcomes aren't 1-1, 1-2, 1-3, 1-4, 2-1, 3-1, 4-1

>>685177709

HAHAHA 50% faggots REKT

REKT
E
K
T

It's 1/3, morons.

>>685178203
But there is no distinction between HT and TH.

Therefore...

>Both are heads
>One is heads

A 50/50, since TT is not an available option.

>>685165589
>chats about murricunts being triggered but still says "math" like an ameritard
get rekt

>>685178203

but OP eliminated one of those 4 equally probably outcomes, rendering two of those outcomes to mean the same thing

OPs premise is that one coin will be heads

once we have that information, all that matters is what is the probability that the other coin will be heads?

since the probability that the other coin will be heads is 50%, the answer is 50%

once you know that one coin is heads, all that matters is the unknown coin

OPs case identified the unknown coin as having a 50% chance of being heads (by being a balanced coin) ergo the answer is 50%

see >>685177436
again and re-read it until it gets through your thick skull

>>685163413
This is what we call a paradox fuck off OP
dont be a fagfag

Head Head
Head Tail
Tail Tail

Can't be Tail Tail
1/2 -> 50%

>33% fags pretending one coin is different to the other

>>685178065
Oh gawd...

If the first you flip is heads there is a 50% Chance you get another Head
If the first you flip is tails there is a 100% Chance to get heads

Since the first flip has equal prob
To get heads or tails the probability of
HT cant be equal to TH righ

>>685178349
>By your logic, it would be 1/7

that's the correct answer.

>but it's not because the possible outcomes aren't 1-1, 1-2, 1-3, 1-4, 2-1, 3-1, 4-1

Those are all the outcomes with at least 1 dice landing on 1.

You just proved yourself wrong. Well done.

Answer to OP question is 1/3.

Washington University agrees >>685177709

>>685177709
It would appear that this is the definitive answer ... well done

>>685178430
>But there is no distinction between HT and TH.

Yes there is. You're just too dumb to undersand even though it's been explained here >>685168469


Answer = 33%

Coins were flipped. If it has already been decided that one of them is going to be heads in this hypothetical, then it's 50%. If, by chance, one of them happens to be heads, then it's 1/3.

There you go you retards.

>>685178662
so when i make a bet with a friend i should always bet on tails because heads has 1/3 while tails has 2/3 chance?
>the jews rigged our money
is the side with tails heavier?

>>685163413
One of them is heads. This means only one is unknown. Hence 50% chance.

>>685178537
>rendering two of those outcomes to mean the same thing

No. TT is eliminated.

HT and TH and HH remain possible and equally probable

1/3

>>685178584
and Tail Head

1/3

>>685163413
1/3
Think about how you would actually do this physically.
1. First you would keep flipping the two coins over and over until you have a sufficient data set. Chances of HH, HT, TH and TT are all equal and 25%.
2. Next you'd look through your data set and remove all the entries where neither coins were heads. Which is only the 25% of TT entries. You're left with the three other options which are all equal still and are now each 33.33...%.
3. Out of the data you have left, only HH entries fit the description we're looking for. So 33.33...% or 1/3.

all the pseudo-intellectuals forgetting that if a chance has it's outcome decided then it's not relevant

if you flip 5 coins and the first four flips were heads then the next flip still only has a 50-50 chance of being heads or tails. it's only a 1/32 chance to get heads 5 times in a row. what's already been decided doesn't matter

I doubt I'm explaining this well, but I hope someone understands what I'm trying to say

>>685178795
1-2 = 2-1, 1-3 = 3-1 and so on

they are not distinguishable

>>685178994
This lad is correct, you are all sniffing you own pretend intellectual asses to much.

The answer to this question based on the info provided is 50%.

>>685179005
You are from burgerland right?

In this experiment the chance of heads increases to 100% if the first flip is tails because one has to be heads

>>685178994
>If it has already been decided that one of them is going to be heads in this hypothetical
>going to be
>in the future

Meanwhile in reality
>2 regular coins were flipped
>were
>at least one landed heads

33%

>>685179009

Either coin could be tails, just not BOTH

HH
HT
TH

1/3

>>685179154
We are not doing the question physicaly its a hypothetical question, and thats why you are wrong.

>>685178905

put two coins on the table

make sure that one of them is showing heads, you know which one, but i won't know which one

cover them both with your hands

slide the hand hiding the unknown coin forward

I'll bet $1 that the unknown coin is heads

if you're willing to pay me $3 if I'm right (backing up your belief that the answer is 33%, and paying me true odds), then you really believe your answer

but, since you will only be willing to pay me $2 if I'm right, that proves that you know that the answer is 50%

otherwise you're just a faggot spouting blah blah blah bullshit

>>685179154

Good explanation.

I see now why it is 33%

>>685179229
>1-2 = 2-1, 1-3 = 3-1

You're retarded.

>>685179386
but if i throw two coins from the top of a building, will the one landing on heads fall slower because of tails additional weight?

i get it how u get 33% but why the fuck would you do this is what i dont get at all?
why are you doing 50% extra work? why dont you just auto place the 1st coin always on heads? and flip only 1 coin cause only 1 flip in reality matters?
can some one explain that to me?

cause the way i see it is youre doing 2+2=4 but for some reason you do it like 2+(4/2)=4 why?

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>>685179383

University of Washington Math Department says 1/3

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

>>685163413

It's always 50/50 u niggers

It simply will or it won't

>>685178994
To anyone still arguing just read this, you're all correct but you're still autistic

>>685179183

You're trying to explain the Gambler's Fallacy.

OP's question does not contradict eh Gambler's Fallacy.

Answer is 1/3

>>685175910
It does but let's say you throw it 10 times, statistically you should have a one side 5 times and the other 5times right? But just because it statistically says it will happen doesn't mean it it will happen. Because you could get 7/10 on one side and only 3/10 the other.

>>685179864
The question stated in your image is not the same as OP's.
Stop trying to push your bullshit washington shit onto people.

>>685179154

but in your scenario you were flipping coins and not knowing until after your flip if either coin was heads

OPs scenario is that we KNOW one of the two coins is heads already

that's what makes the answer 50%

it changes it from 4 possible outcomes to two possible outcomes: one head and one tail, or two heads

therefore, 50%

>>685179573
>put two coins on the table
>make sure that one of them is showing heads,

That's not the same as the OP question.

Answer to your scenario is 50%

Answer to OP question is 33%

>>685163413
I just make sure your mom is with me, always head when she's around, faggot

>>685179383
No it isnt
first flip 50% Head
Second flip:
If 1. Head then 50% Head
If 1. Not Head 100% Head

So it would only be 50% all in if you knew which one would be a Safe Head but you dont know that

>>685180245

OP said "one is heads"

how the fuck is that any different than what i wrote you autistic faggot?

>>685179821
>why dont you just auto place the 1st coin always on heads? and flip only 1 coin cause only 1 flip in reality matters?
you're beginning to see the fact that they're just pseudo intellectuals.

it's a 50% chance. the fisrst coin doesn't matter because we know its state. sure, you have a 1/(2^100) chance of flipping 100 coins all heads one after another, but if you already flipped 99 heads, then your next coin still only has a 50% chance to be heads and a 50% chance to be tails

>>685179821
>and flip only 1 coin cause only 1 flip in reality matters?

You still don't get it.

>>685179420
Two coins were flipped, yes, but OP's question didn't specify whether they have fallen on their face yet before we know that one of them is heads.

So basically it's an ambiguous question with no true answer, OP is a faggot, and you're all baited.

>>685180332
It doesnt matter, it is "given" one of them is heads.
How can people be good at math but so bad at reading a fucking english sentence correctly.

>>685180086

>50% faggot REKT
>i-it's n-not the same

kek

Mathematically 1/3 is the right answer. The whole question is worded strange, but I think we can all agree that both coins being tails is impossible in this equation. So now we are left with 3 options. There is no arguing that thatafter this point in time after deducting one of the four outcomes that we now have 3 outcomes.

Since once of these is GUARANTEED to have a heads we can assume that the three outcomes possible contain a head, which after the deduction we can noe confirm as TRUE.

Now the final part of the question is what is the possibilty that BOTH of these coins are HEADS, while remembering that it is IMPOSSIBLE for both to be tails.

Mathematically 1/3 stands. Both coins have an equal chance of being tails so there is a 2/3 chance that we will not get the ideal.

Dont say that these to results are the same and that it is 1/2. Nothing in this question can draw the conclusion that we know which coin has landed heads

Its 1/3
No one coin is guaranteed heads
People are saying 1 flip doesnt affect the other but it does, if first coin is tails the other is guarenteed heads if first is heads it can go either way
3 possibilities
C1=tails then c2=heads
C1=heads c2=tails and
C1=heads c2= heads
1/3chance heads twice

>>685179779
No you retard they will vaporize before tails maxes its speed... Fucking burgers...
How can you even tie your shoes

>>685180118
>one head and one tail, or two heads

There are 2 ways to get one head and one tail

1/3

>>685164365

It's 50%. Regardless of what they tell you in school, it will remain 50%

You fucking retard

>>685179924
Not really, the question specifically states its two regular coins, which by definition have a 50% chance of being either heads or tails. If you assume one will always land on heads, you do not have two regular coins.

The only correct answer to this question is 1/3, because the phrasing of the question indicates we will flip two regular coins and disregard the non-conforming TT results.

If the question was looking for the 50% answer, it would instead ask "You have 1 regular coin and one loaded coin that always lands on heads....."

>>685179872
Lottery is 50/50 you win or you dont