can /r9k/ solve the hottest meme puzzle currently making rounds on 4chan?
50% you stupid niggers
>>27653192
75%? o r i ginalllduncfnvdkmssjn
>>27653192
LOL, he said balls :3
>>27653241
First post was correct
/thread
>>27653192
50%
You know it cannot be the third box because there are no gold balls in that
there is just as much of a chance of the second ball being gold as there is that of it being silver
What's the point in mentioning there's a box with 2 silver balls?
2/3 because you picked one of 3 gold balls and in 2 of those cases the other ball is also gold
>>27653192
yeah its 50% obviously but what annoys me is that the question mentioned the boxes in a different order as to how they appear in the image, just lazy desu
>>27653283
how would you know which one is the box with the silver balls?
>>27653192
2/3 according to Bayes theorem.
>>27653192
66% chance of picking a box with a golden ball in it, 50% chance of there being another golden ball and a 33% chance of actually picking a box with 2 golden balls.
>>27653421
But then why is the reverse 2/3 for silver too?
>>27653192
33% niggers
chance of picking box with 2 gold balls = 33%
>>27653192
100%
0%
0%
so roughly 33% repeating chance that you'll draw another gold ball.
>>27653494
It's not. It's 1/3 unless you pick a silver ball, in which case it drops to 0% naturally.
>>27653494
Why shouldnt it be? Sum of probabilities is 1 only if the events are independent.
okay so the setup is you have 3/4 chance to get a gold ball because the box with two silvers is effectively ignored per the prompt.
now you have 1/2 chance of getting another gold ball because you could have either 2Gs or 1G 1S, again per the prompt.
so the probability is 50%. or if you want to be a good goy, it's (3/4) * (1/2) which is (3/8) * 100 percent chance.
>>27653241
>50% you stupid niggers
One gold ball is already drawn, leaving the ratio 2 gold 3 silver (remaining).
This means the total percent that it could be cannot be equal to that of HALF because there is less than HALF gold balls remaining.
>>27653519
Yeah, but it's not saying which ball you take at first, though. It could be gold or silver..
>>27653192
Muh theoretical probability problem. Fk u
>>27653402
it doesn't matter - you ignore the box with the silver balls because you already drew a gold ball.
it's 50%, I don't give a shit
you either grabbed from the first box or the second. it can't be the third.
Event A: You picked a gold ball.
Event B: The next ball taken from the same box is also gold (you picked the box with two gold balls)
The probability of B given A is the probability of (A and B) divided by the probability of A, by Bayes' theorem.
The probability of (A and B) is the probability that you picked a gold ball, and that the next ball taken from the same box is also gold.
This is the same as the probability that you picked the box with two gold balls, because these events are not independent.
Therefore the probability of (A and B) is 33%.
The probability of A is the probability that you picked a gold ball.
There are three gold balls out of a total of six balls, so of course this is 50%.
Thus the probability of B given A is 33% divided by 50%, which is 66% (0.333333... / 0.5 = 0.666666...)
>>27653541
hey fucktard
you are given a gold ball, which means you drew from 1 of the 2 that hold gold balls
if you draw from the SAME box, then it can either be 1 silver or 1 gold
50%
>>27653192
>>27653614
>orofinL
>>27653614
Why do you divide the two? I'm trying to visualize it.
>>27653614
So if you're telling me that if I conduct this experiment 500 times, I'll get 2/3 rather than 50%?
>>27653192
>It's a gold ball
HAHAHAH oh my God. Sorry, I apparently can't even read a question.
>>27653548
>but it's not saying which ball you take at first, though.
hahahahah. This is why I can't do anything right. I /never/ read the question right.
>>27653192
It's got to be 50%
You can wank all you want over bullshit impractical math theorems but if you were to repeat this process over and over again it would be around 50%.
>>27653677
Yes. It's counterintuitive but it's true.
Stop spamming some shitty Highschool problem.
Anyone who has gone to HS will know how to solve it and that human intuition is in statistics misleading.
It's 2/3 not 1/2
If you are given that pick 1 is gold, box 3 is out. Then there are 3 ways to have arrived at pick 2. Call gold balls from left to right 1,2,3
Pick ball 1 = 1/n = 1/3
Pick ball 2 = 1/n = 1/3
Pick ball 3 = 1/n = 1/3
Sum the prob of each box
Ball 1 chosen from box 1 2/3 times
Ball 1 chosen from box 2 1/3 times
Success condition is if ball 1 comes from box 1 and fail condition is ball 1 chosen from box 2
Therefore p(next gold, under 1 gold) = 2/3
Sorry I do not speak English well
>>27653614
The fact that you already picked a gold ball rules out the box with only silver balls, thus leaving 2 cases: you picked the box with 2 gold balls or the one with mixed balls. Hence the chance the other ball in the box is also gold is 0.5.
Bayes' theorem doesn't apply here.
>>27653725
No if you repeat many times, approaches 2/3, because of given condition implies conditional not independent probability
>>27653677
>>27653731
https://www.youtube.com/watch?v=tvODuUMLLgM
>>27653614
If you already pick one of a certain colour, that mean's there will be 2/3 of them left based on which possible box you have.
You can say it simpler by this way.
this is just the monty hall problem, with the scenario changed slightly
it is STILL 66%, and will remain 66% forever
>>27653775
>derp derp fart derp poop
That's all I hear from your stupid face, it's 50%
>>27653759
Think of it this way. There are 6 possibilities for which ball you draw first, all with a 1/6 probability of occurring.
You know that the first ball you drew was gold, therefore you know with certainty that either event 1, 2, or 3 has occurred.
In the case of event 1, the other ball is also gold.
In the case of event 2, the other ball is also gold.
In the case of event 3, the other ball is not gold.
Thus, in two of the three scenarios, the other ball is gold, giving a 66% chance of finding another gold ball.
>>27653849
It's from the same box you fucking curry nigger. Box three is irrelevant.
>>27653873
Where did I mention box 3 being relevant?
Point it out for me.
The answer visualized.
>>27653849
Got it now. I did not account for the fact that picking a gold ball first is a posibility among 3 events, not 2.
This is just a modification of the monty hall problem. Basically, when you first pick a golden ball at random you have a higher chance of picking the ball from the box with 2 golden balls in it rather than the box with only 1 golden ball. Therefore, you have a higher chance that the secound ball you pick is also a golden ball instead of silver.
>>27653849
Event 1 and Event 2 are exactly the same. It doesn't matter WHICH gold ball you choose, just that you pick a gold ball.
>>27653910
You don't get to switch boxes, you need to pick from the same box. The probability of picking gold/silver from the other box is irrelevant.
>>27653622
>if you draw from the SAME box, then it can either be 1 silver or 1 gold
Lol and you're the one calling me a fucktard? There's dynamism to this question because you're reasoning that you drew the gold ball from the one that has two gold balls. Guess what? Two of them have gold balls (so there are two options in this case, meaning 50% is an inapplicable answer).
You have to ignore the boxes and pay attention to the total sum of gold vs silver balls. There are six in total. One is removed. That leaves 2 gold and 3 silver. That means that there is less than half an equal amount of Gold to Silver balls.
TL;DR you're dumb cause the probable chance of pulling it is less than 50% mandatory for the simple fact that there is one less gold ball in the equation meaning there's no longer an equal sum of gold and silver.
>>27653950
see >>27653939
The outcome of those may look similar, but still are different events.
>>27653951
But it is guaranteed that your first draw is gold, so we don't know from which box it came from. This means you can treat any gold ball as the selected one, and just simply count how many gold remain of total.
>>27653977
A gold ball is a gold ball, you can't say it's not the same
>>27653950
There are twice as many gold balls in the first box as the second.
Given that you picked a gold ball, it's more likely that you picked box 1 than box 2.
Thus it's more likely than not that the next ball is gold too.
Event 1 and Event 2 being exactly the same would imply that box 1 only has one gold ball, and that you put it back before you draw again, which is a different scenario.
>>27653756
none of that is relevant.
>>27653954
Not him but if you pull out a gold, does t that eliminate the possibility of it being from the 2 silver ball chest, thus taking out 2 silver balls from the equation? I dunno, help me falim
The problem with you autists claiming it to be 50% is that you assume that box 3 is irrelevant, it isn't. The experiment isn't conducted in a vacuum which only contains first two boxes, there will be many cases in which you pick a silver ball first, the very fact that the fist ball you chose turned out to be golden implies that there was a high chance that the box you picked was the one that contains 2 golden balls, hence the probability of the second ball being golden is higher than 50%. It is 2/3 by baye's theorem and which is what the actual probability is. Just ask yourself: If I picked a ball and it was golden which is more probable, that I picked from the box that contains two golden balls or the one that contains only one?
>>27653954
Shut the fuck up. If you've already drawn a gold ball and you know that one box has 2 gold balls and one has silver.
The box with 2 silver balls has no bearing here because you already know it isn't that box. It's either going to be gold or it's going to be silver if it was the box with 1 gold and silver.
50%.
>>27654029
>there will be many cases in which you pick a silver ball first
Except that isn't what this problem is about. It specifically says you picked one golden already. You know it was either from the box with 2 gold or 1 gold and 1 silver. That's 50%.
It's only asking for this one specific pick. Not other tries in which you may have picked a silver first. It's irrelevant.
Because according to the problem you will pick the ball from the same box you picked the first gold one from.
>>27654071
>Just ask yourself: If I picked a ball and it was golden which is more probable, that I picked from the box that contains two golden balls or the one that contains only one?
>>27653759
There being two events possible doesn't mean each is equally likely to occur. This is the equivalent of saying there's a 50% chance a robot will get a date from their oneitis because there's only two outcomes
>>27654087
>which is more probable
Neither. Because you know it will only be gold or silver. Since you already drew the first gold ball you know you're either picking from the box with a silver ball left or a gold
This is more of a a question of interpretation than probability.
>>27654014
The only silvers box is ruled out indeed.
See >>27653910
>>27654112
Either way, it's still 33%.
Its 66 percent retards
Only 3 possible results for his next ball, because the box with only silver is eliminated.
A gold ball
A gold ball
A silver ball
66 percent chance his next ball will be gold
>>27654087
You're backtracking to a step that already occurred and is currently irrelevant to the actual question being asked. You're just like the guy who was talking about the double silver box as if it was relevant to the question.
>>27653910
>Disregarding important static variables.
You may have drawn 1 gold ball, but you still have a 1/3rd chance to draw the box with all silver. You're straight up leaving out valuable variable information here.
>>27654139
You need to pick from the same fucking box senpai, it's either a gold ball or a silver ball.
>>27654139
>Only 3 possible results for his next ball, because the box with only silver is eliminated.
where are these Meme-maticians coming from? You have three boxes. You can NOT eliminate a box simply because it doesn't have gold. All three are drawn from (or have potential to be drawn from) where the fuck do you eliminate it, please enlighten me.
>>27654161
SAME
BOX
You guys are acting like you can just pick from whatever box you want or something.
>>27654161
The question says that you picked a gold ball first meaning that the box containing only silver balls can be ignored.
2/5ths you niggers.
You already took one.
>>27654112
OK, consider this I am naming the box with two golden balls G, and the one with one golden ball B.Now the names of balls in G are g1 and g2, the name of golden ball in B is g3 and silver one's is s. Now I am only considering the cases in which a golden ball is picked first, so the cases are
g1 g2
g2 g1
g3 s
In 2 out the 3 scenarios the second is also golden, therefore the probability is 2/3.
>>27653954
>You have to ignore the boxes and pay attention to the total sum of gold vs silver balls.
you don't because you know (because of the question/task) that you drew from one of two boxes that contain gold balls. so your chosen box contains either another gold ball or it is the box with the gold&silver balls. I can't be the box with the two silverballs. Guess what, I sometimes have blue balls!
2/5
There are 2 gold balls and 5 possibilities total. Any other answer is a meme.
Nope, it's 50% not 66%. This is 900k trials
>>27654176
Because we are picking from the same box, and since we know there was already a gold ball in this box, we know this definitely aint the hox with two silver balls
>>27654166
But we don't know what box we picked out of right?
I do see where you're coming from tho. The box you picked out of had a gold, that means the next one you pick can be from the gold-gold box, but since you have one gold in your hand, there's only 1 gold you can get there. You could also have the gold-silver box, and since you have the one gold in your hand, you can only pick the 1 silver. 1gold vs 1 silver, 50/50. Wait... Now my head hurts...
50%?
Did I do my statistics right?
>>27653660
>visualising a maths question
How to spot the autist.
>>27654176
CONDITIONAL PROBABILITY
>>27654219
why didn't you show the definition of randomN faggot?
If you're guaranteed to pick the gold ball then you can't possibly be picking at random. The puzzle makes no sense.
>>27654219
this is some shit code with useless variable names senpai
>>27654256
go be retarded somewhere else
new trial, 1.2 million
>>27653192
For anyone who believes it's 2/3 is assuming that you pick box 1 twice as often as box 2. this is wrong. you picked up a gold ball. that condition disregards the 1/3 chance you'd pick box 2 and now you are looking at 50% of the time you opened box 1, and 50% of the time you opened box 2. the box determines the color of the ball.
it's only 66% if you pick from any box after the first one. you are all FUCKING RETARDED
>mfw people trying to convince anyone not saying 66%
spidey thread?
>>27654284
>>27654219
>>27654275
these
It's 50%, this is 6th grade shit
>>27654294
Back to another site you should go
>>27654317
and 2/3 by 11th grade shit.
These "puzzles" don't have a correct answer because it's up to interpretation. Meme puzzles like this are intentionally made to get autistic STEMlords to argue with each other kek
>>27654347
No you dumb autist. This puzzle is perfectly well defined and it's easy to simulate like someone just did. The one that is "up to interpretation" is that "50% critical strike" bullshit which contradicts itself.
>>27654342
Go look at my algorithm and try to find a flaw. You can't. It's 50%.
12 million
I hate monty hall puzzles that arent actually monty hall puzzles
>>27654275
>>27654219
>>27654371
What do you say to this then?
Guys it would be 50% if you KNEW you were picking from a g/s box. But we dont know that. It could possibly be the g/g box we are picking from
You need to stop thinking of it as two different boxes, g/g and g/s
And think of it as one big box that contains three balls, g/g/s
Meaning 66%
>>27653834
Nice observation senpai. This is a much simpler phrasing of Monte I think.
>>27654402
you need to try again after you've learned how to read in english.
>>27654378
try using a non-meme language
>>27653910
? What? I'm confused. Can someone explain the difference and what's happening here?
>>27653402
You already drew a gold ball, so you can be 100% certain that you did not pick from the box which has only silvers in it.
>>27654284
now when i think about it's fucking 50%
i can't even explain it that well but i fucking understand it
fuck man
>>27654452
the difference is the guy you replied to believes that you pick box 1 twice as often as box 2. which would mean there are two boxes with two gold balls.
>>27654378
>>27654371
Literally no one can argue this
>>27654371
The code is embarrassing.
>>27653192
It's 1/3.
It's the goat problem in a different form.
Basically: the only choice you actually make here is when you have three boxes, and the end result you're looking for is that you're picking the box with 2 gold balls. That's a 1 in 3 chance.
Everything else inbetween is flavour text. Because when you made your choice you had a 1 in 3 chance of getting a two gold balls box. Going on to confirm if this has happened after observing 1 gold ball (and thus eliminating one of the possibilities) doesn't change the fact that when you made the choice you had a 1 in 3 chance at picking it.
Imagine that instead of 3 boxes, you had 8000. 7998 are silver, one is gold and once is silver/gold.
You pick a box, you check one ball. It's gold. What are the chance the other is gold? Still pretty low - because when you chose your chances of finding either box with gold balls was low.
Observing halfway through verification doesn't change the underlying odds.
You have 2/3 chance of picking a box w/ a gold ball in it.
You have 3/4 chance of the first ball being gold.
You have 1/2 chance of having picked the box w/ 2 gold balls in it.
Therefore you have 2/3 * 3/4 * 1/2 chance of the second ball being gold as well.
it's clearly .75
wow you guys are dumb
>>27654371
Here's why it's 50%
3 boxes, in terms of gold balls we have
2/2...........1/2...........0/2
you pick a box at random, it has a gold ball so it HAS to be
2/2...........1/2
now from there, you choose again, so two paths branch of
1st path:
2/2; you get a gold ball
there is a gold ball remaining, 100% of gold ball
2nd path
1/2; you get a gold ball
there is a 0% you get a gold ball (since you took the only one)
(50% + 0%) % 2 = 50%
>>27654378
Your algorithm is wrong, read my post
>>27654487
>int box0 = 2;
>int box1 = 1;
>int box2 = 0;
this guy is retarded, if the fact that he's using a mac wasn't evidence enough
>>27654493
it would be the goat problem if someone showed you the 2 silver balls and you could choose between the two remaining boxes.
Im mad that im getting trolled ;(
>>27654477
>using kik
Gtfo normie
>>27654452
You are ruling out the fact you could have picked the other gold ball in the all gold box.
>>27654511
that was to help me visualize the shit, notice how it's commented out. it's basically saying that the first box has 2 gold shit, the second one has 1 gold shit, and the last one has 0 gold shit
it's still 50%, inbred
>>27654526
You either choose the 2/2 box or the 1/2 box.
if you choose the 2/2 box, 100%
if you choose the 1/2 box, 0%
hence, 50%
>>27654515
But you *have* essentially been shown the goat - because you know you have one golden ball.
It's exactly the same as if you phrased the question as someone opened one of the remaining boxes and showed you two silver. in both cases you've eliminated one option.
>>27654505
No. Read the comments in my code, they follow the problem exactly as stated.
Tell me where my code is wrong. Don't say "It's wrong, look at my thing."
Show me which part of my code is incorrect.
>>27654526
No you aren't. You've picked one box of two, both with an equally likely chance of being chosen.
Since we don't know which box we have chosen, and since the first one is gold, we can cancel out one gold ball from each box. That makes 1/2 remaining.
>>27653192
>>27653477
my bad have to make a correction its a 50% chance of picking a box with a golden ball, 50% chance of there being another golden ball and a 33% chance of actually picking a box with 2 golden balls.
>>27654555
Here is your mistake. The third box needs to be eliminated since the problem can only continue if you have a gold ball, so the third box doesn't actually exist in the problem space.
>>27654602
Where does it state that in the problem?
The problem says you pick a box at random. This could include the box with two silver balls.
You then take a ball from that box, also at random.
If that ball is not gold, then this trial is discarded, and times_first_ball_was_gold is not incremented.
Discarding the trial is not the same as not considering it in the first place.
>>27654275
long variable to store a number less than 3 lmao kys
>>27654602
Not that guy but; you're wrong about that.
You know you made a choice when the chance of getting a two gold box was 1/3. Everything from there is confirmation.
This is especially true if you're running a mass simulation, otherwise you're eliminating all the times you chose silver/silver - but the problem explicitly states that that was part of the potential problem space when you started.
The answer must contain the possibility you picked silver/silver.
HOW IS THIS AN ARGUMENT
IT'S 50%
YOU PICK A GOLD BALL, SO THE SILVER BOX DOES NOT MATTER. IT IS A RED HERRING.
>>27654493
you cant explain the solution exactly the same as the monty hall problem, since the conditions are slightly different
monty hall is 3 choices, 1 is revealed as wrong and you are left with two options, it ends up being 66% to win assuming you switch. with 100 doors, you pick one and 97 are revealed to be wrong, leaving your one and another. this means out of the 100 doors you first selected from, its most likely you picked the wrong one, meaning if you switch you get the right one since all other incorrect options apart from your selection (which was 99/100) of the wrong door
this has another layer to it, and comes out to a different result as the monty hall problem
you select a box, though one box with no gold balls is already eliminated - "you put your hand in and take a ball from that box at random. it's a gold ball"
this means you either selected the 1 gold and 1 silver or 2 gold ball box. now memes and arguments come from how to represent this fact. representing it as a conditional probability will make it come out to 50%. you remove the 2 silver ball box, as it does not fit the condition of picking up a gold ball. now you have only 2 options. you either selected 1 gold 1 silver box, and don't pull out the 2nd gold, or you select the other box and pull out the 2nd gold. this means 1 out of the 2 options gives you a 2nd gold. 50%.
if you represent this as just the probability that you will pick a 2nd gold ball, disregarding the condition you get 1/3, only 1 of the 3 boxes that you pick will yield a 2nd gold ball.
however, since the questions gives us a condition and states "what is the probability that the next ball you take from the same box will also be gold?" right after giving us the condition logically means that we use the first explanation to this and thus, is 50%
>>27654565
This. I actually converted sides. :( 1/2, you guys.
>>27654553
no. you haven't been shown shit. you just know that you picked one of two boxes with a gold ball in it. you don't know which one, and you have eliminated the other boxes altogether.
>>27654552
>>27654565
If you pick from the 2/2 box, it could be any of it 2 gold balls. Thats why the total cases are 3, not 2 as you are stating.
Case 1: You pick a gold from the 2/2 box. Outcome: the other ball is gold.
Case 2: You pick a the other ball from the 2/2 box. Outcome: the other ball is gold.
Case 3: You picked the gold from the mixed box. Outcome: the other ball is silver.
3 cases equaly likely to happen, in wich 2 outcomes are the other ball being gold.
>>27654671
>pick at random
>pick box 1 2X as often as box 2
nice.
Say the first box contains gold balls "a" and "b", the second box contains gold ball "c" and silver ball "s".
The first ball you take is gold, which means it's either "a", "b", or "c". Each of those balls has a 1/3 chance of being selected.
If the first ball was "a", the second will be "b". If the first ball was "b", the second will be "a". If the first ball was "c", the second will be "s".
2 out of the 3 possible outcomes for the first ball selection will lead to the second ball being gold. (2)(1/3) = 2/3
>>27654087
It is not more probable to pick from the box with 2 gold balls in a case where drawing the gold ball first is 100 percent.
You have drawn 1 gold ball from a box as a prerequisite. The odds of drawing this gold ball were 100 percent, even in a box of 99 silver balls. So if you have taken 1 ball out of a box containing 100 balls, and there is a certainty that the remaining 99 balls are a single colour, then you have a 1 in 2 chance of drawing 1 color or another.
I change sides, it's 50% I think
Stop thinking about two different boxes. Put it in simple terms. You have only one box you can pick from and it has only ball in there, either a gold ball, or a silver ball. 50%
>>27654639
>>27654654
It's not stated, but implied and this is why;
The problem says you pick a box at random, but then it says you pick a ball from the random box and it's gold. That's impossible if you pick the third box, so it doesn't exist in the problem space. It's there intentionally to confuse people.
>>27654671
That's wrong because case1 and case2 are really the same.
You either choose the 2/2 box or the 1/2 box.
if you choose the 2/2 box, 100%
if you choose the 1/2 box, 0%
so, 50%
>>27654711
>picked the first box 66% of the time
>random
>>27654721
The odds of drawing a gold ball first are 100%, but it's still twice as likely that it came from the box with two gold balls.
There's three gold balls. You'll draw a gold ball 100% of the time, but it's random which of the three balls gets picked, so you're more likely to draw from the box with two gold balls
>>27654747
>i don't understand how conditional probabilities work
>>27654602
this guy is right, I bet if you fix that in your program you will get 50%
>>27654452
This illustration did it for me. It's actually 1/2, no doubt about it.
>>27654696
You are not really picking at random, as the problem states your first pick is already gold.
There are 3 chances of the 1st pick being gold, 2 of them from box 1 and 1 from box 2. Thats why, given the fact the 1st pick is gold, the chance you took it from box 1 is twice that it being from box 2.
>>27654771
>it's random which of the three balls
>picks the first box twice as often as the second
>random
>>27654771
I want this to click on my mind. I'm in the bargaining stage of grief now. How can gold be real if our odds aren't real?
>>27654779
But that's not what the problem says.
I wrote the code exactly the way the problem is worded, and the results speak for themselves.
>>27654565
FUCK. We have the draw from the same box too! Fuck, motherfucker. Yes.
>>27654801
>it's random whether it's going to rain or not
>rains 20% of the time
>random
this is how dumb you sound
its 66% with 3 boxes and with 2 boxes. no matter how you calculate it
3 boxes: you draw the gold ball. this means that you didnt pick from the silver box. you now have chances of having picked from the two boxes that have gold
2/3
2 boxes: lets say you dont really get the puzzle. you only calculate the two boxes containing gold balls: there are 3 gold balls and one silver. You take one gold. 3 remain and 2 of them are gold
2/3
>>27654801
You pick a ball at random. It can be ball 1, ball 2, or ball 3.
Ball 1 and ball 2 are both in the same box. The odds of picking that box are 2/3.
>>27654792
the problem states you selected from three boxes, not from 3 balls dummy. if you selected from three boxes, each box had an equal chance of being selected. given that you pick up a gold ball first, you exclude the probability that you picked box 3 and you are left with a 50/50 split on ball #2.
you are imagining a completely different problem where someone knows that box 3 has no gold balls in it.
>>27654772
>I'm a retarded that doesn't understand when conditional probability should be applied but I like to pretend like i know what I'm saying by meme-texting
If you want to make a point, make an actual point instead of pretending to be retarded.
>>27654804
You were memed by the problem. It's impossible to get a gold ball from the three boxes, only in two of the boxes is it possible to get a gold ball from. That is implied, you were supposed to factor that into your program. Your program is only right if you factor that into it. It's wrong otherwise since the third box doesn't exist in our problem, it's a red herring.
>>27654845
you pick a box at random, and you take both balls out of it.
box 1: 1/3
box 2: 1/3
box 3: 33%
50% of the time you picked out 1 gold ball, you also picked out a silver one. CUNT
>>27654869
You can't pick box 3. The problem states that the first ball you pick is gold 100% of the time.
in EVERY one of these threads there are retards who dont know how probability works...
>YOU CANT KNOW SO ITS 50%
holy shit shut the fuck up and try reading a book
>>27654850
You didn't actually select from three boxes though. The first ball you take will always be gold, which means you will always select one of the first two boxes.
>>27654850
Rule out box 3 completely.
See >>27654671
I never took box 3 in consideration.
>>27654853
I've explained this like I would explain it to a literal retard, so if you still don't get it by now there's no helping you.
>It's impossible to get a gold ball from the three boxes, only in two of the boxes is it possible to get a gold ball from.
This is not wrong, but it doesn't factor the third box out of the problem.
It means we simply discard trials in which the first ball drawn is silver.
There's an important difference, and my program does exactly this.
>>27654881
no it doesn't. it's saying you have already picked a gold ball on a single selection. you selected one of two boxes either way. you didn't select 1/3 gold balls.
>>27653192
I don't care. These boxes are full of gold and silver balls. I'm taking them and I'm selling the balls.
The real question is what is the probability of me being robbed or ripped off while trying to sell the balls.
Lesson learned:
>Just because someone says "Hurr durr use the ____ theorem", it doens't mean they know what they are talking about.
>>27654917
if you rule out box 3 you are left with two boxes, 50% chance of selecting either one.
if you had 2 gold 2/3 of the time that implies that you selected box 1 2/3 of the time. flip a fucking coin and see if that's true.
>>27654747
Discarding instances where you pick box 3 is the same as it being impossible. His code is correct and otherwise you are misunderstanding that the two gold balls in the same box are different entities that must be considered individually, leading to 67%.
>>27654922
>but it doesn't factor the third box out of the problem
Yes, inbred, that's exactly what it does. The problem states that the first ball is gold and asks for the possibility that the next ball is gold. With the third box, it isn't possible to get a gold box, hence it doesn't exist as part of the problem. How is that difficult to understand?
>It means we simply discard trials in which the first ball drawn is silver
You're actually retarded. Go read the problem again. The problem beings with you picking a gold ball first, tard. Go from there.
>>27653192
it's a probability math problem. If I could remember anything from my stats classes I'd probably try to figure it out.
>>27654452
>>27654565
Let's combine these two posts and make a general statement on behalf of all 50% proponents.
We can all agree we can rule out the all silver box.
This makes 2 boxes remaining. We are to select one.
Each box has an equally likely chance of being chosen and we are told the first draw is gold.
Both boxes contain a gold ball, so with this knowledge, we still don't know which box is chosen, both are equally likely, so we can actually omit a gold ball from each box.
What remains is one gold and one silver in each box, and this is 1/2.
Literally indisputable.
>>27654969
>Discarding instances where you pick box 3 is the same as it being impossible
Yes, at that point you have two boxes, one has 2 gold balls, the other has 1
you PICK a gold ball
this means that you either picked 1 of two gold balls and have 100% chance to pick another one or you picked 1/1 gold balls so you have 0% of picking another one (since you pick from the same box)
hence 50%
>>27654955
You indeed pick box 1 as twice as box 2.
Read my post, and try to understand it.
>>27654978
No, the problem begins with you picking a box, then a ball.
Then it states that you know that the ball is gold.
>>27654998
you don't understand the problem at all
>>27654995
No. Reread what everyone has said to the contrary with an open mind and you will learn a valuable lesson.
>>27654982
>Each box has an equally likely chance of being chosen
This assumption is wrong.
50% autists BTFO:
http://ideone.com/0OKqBr
>>27655049
Are you kidding me?
What factor is responsible for making the likelihood unbalanced? They are just boxes that look the same on the outside.
>>27653192
But if you can't see into any of the boxes then how do you know what's inside them?
Checkmate.
From the same box is the keyword. The box you had pulled from already had one gold ball.
The choices left are gold or silver for the remaining ball.
It's 50%
Anyone who says otherwise should reread it. You are pulling from the same box and there are only two different choices.Baka
similar problem. this explains why some people in this thread expect 2/3 for the second gold ball. they don't even register in their minds why the boxes are selected at random, because they think we already know where the balls are.
https://www.youtube.com/watch?v=maLzqjYx1BM
>>27655024
I understood it pretty well. I also fell into the catch of thinking that pickin from each box is equally likely.
>>27655028
you pick a box
2/2....................1/2....................0/2
you pick a gold ball from that box
2/2....................1/2....................0/2
1/2 remaining 0/2 remaining [error]
have to change assumptions
2/2....................1/2
1/2 remaining 0/2 remaining
100%................0%
50%
>>27655110
watch >>27655101
you aren't picking from 3 balls, you are picking from two boxes
I actually had to go through the pain of admitting I was wrong, and converted to 50%. Fuck, it is so painful.
>>27655142
don't lie mate, you believed it was 50% all along.
>>27655077
The fact your first pick is already gold imbalances it. It 1st pick is gold it means one of the following happened:
1- Picked a gold from box 1
2- Picked the other gold from box 1
3- Pikced the gold from box 2.
These 3 events are equally likely to happen, and in 2 of them, you picked from box 1.
>>27655156
No, I actually thought it was 2/3 at first. I didn't take all factors of the question into consideration, like picking from the same box.
>>27655176
Picking from the same box changes nothing.
>>27653192
>how to get 200+ replies
no matter how easy these problems are, you retards still argue
There is nothing ambiguous about it. It's 50%
>>27655167
Isn't the first thing you do pick a box at random though, so picking any box should be equally likely
notice me http://ideone.com/0OKqBr
>>27655214
see
>>27654378
for better, more readable code
>>27655167
those events are not equally likely though. you are not choosing between 3 gold balls. the only decision you make is which box you open.
>>27655200
not quite, see
>>27655118
Sherlock Holmes once said, "You must eliminate the impossible, then be left with the possible." or some gay shit
Ok faggots what if there were 4 boxes, another silver/silver
What if there was a million billion additional silver boxes?
>>27655181
Yes, it really does.
If you were told that the first draw is gold. It doesn't matter how many times you drew before that to get a gold ball. You know there are two boxes that remain after drawing a gold ball.
If there are two seemingly identical objects in front of you, you have an equally likely of choosing one over the other.
Since one draw is gold, you still don't know which box you chose.
That means the deciding factor is between one gold ball and one silver ball, which is 1/2
>>27655263
you still have 2 boxes possible. and you picked one of them at random.
>>27655263
Still 2/3
>>27655229
"I can code too!"
What really matters is the logic you use behind the code, which is no different than putting it into words. If the code is missing some important factors in the question, the results will show up wrong.
The answer is 1/2.
>>27655263
picking a gold ball is a, picking a second is b
answer does not change, you baiting fuck
>>27655327
picking a gold ball is b, and picking the second gold ball is a, switched them by accident
Question for everyone who says that the answer in OPs question isn't 0.5
What is the answer to this one?
>>27655326
That was a good post until the last line. The answer is 2/3.
>>27655344
But you were told beforehand that your first draw was gold. It doesn't matter how many times you drew before that to get the gold ball because the question starts with assuming that your first draw is gold. That eliminates every box that doesn't contain a gold ball.. How do you not get it?
50% duh lmao
this is basic shit cmon guys
>>27655344
you still have 3 options you fuckwad
2 golds
1 gold 1 silver
2 silvers
since you picked a gold already it doesnt matter how many 2 silvers there are, 2 options are left that can happen out of three
2/3
HOW DENSE ARE YOU PEOPLE
>>27655344
wow, still 2/3
>>27655387
>3 options
>2 boxes
nice
>>27655387
please PLEASE sterilize yourself you actual retard
>>27655387
Wow, I am thankful, after seeing this post, that I am given the power of logic that others can't see. Because that post was absolutely mad, and it's almost as though they deliberately refuse to take into account the conditions of the question.
>>27653516
But the third box doesn't matter
>>27653192
the box with the silver balls is a red herring
yes, you know you didn't pick from that box because you got a gold ball
but you also need to take into account the fact that since you got a gold ball you're more likely to have picked the box with two gold balls
>>27653192
I feel like there must be a trick, but it really seems like a 50/50 chance; the third box is ruled out.
>>27654944
it depens how big the gold balls are
the silver balls are not worth very much at all unless they are huge
>>27653192
If you don't say 50%, then I have to question anyones ability of basic logic and math.
The question asks the probability of picking a 2nd golden ball from the same box you picked the 1st from; this eliminates the third box since it has no gold balls, which leaves behind two options, one box that has a gold ball remaining and one box that has a silver ball remaining, ergo there are 2 outcomes and only one gold ball left ergo 1/2 = 50%.
>>27655462
There are three ways to pick a gold ball.
If you have a gold ball, it's twice as likely that you got it from the first box as the second.
It's not that complicated.
>>27655436
no you're not. try it at home. flip a coin 20 times, and when you land on heads you can rub your autistic belly. you'll see that the answer is 15%
>>27655436
this is correct, I was a 50%er but I was converted by the program results and now I realize I'm a retard and wish I was dead
>>27653192
50%
the other two boxes dont matter because you have to remove both balls from the same box and youve already removed gold from one of them
easy as fuck
>>27655409
>2 options are left that can happen out of three
you can exclude the third option. learn to read retard, its 2 options for 2 boxes
>>27655410
lets hear your 50% solution
>>27653192
2/3 gold balls are in one box, so it's 2/3 you'll have picked that box and that the next ball will be gold
hey guys after reading this thread i am sure that half of the people saying 50% is right are just trolling and the other half is just stupid like >>27654886 said
>>27655405
Where are you selecting which box you choose and starting over if the first draw does not equal gold?
>>27655584
>where are you selecting which box you choose
box = boxes.sample
>and starting over if the first draw does not equal gold
if box[first_ball] == :gold
...
end
If it's not gold, this obviously is skipped.
I'm refactoring it a bit to make it even more clear at the moment.
You picked a gold ball. There are three ways this could have happened. Either you picked the first box, then the first ball, you picked the first box and picked the second ball, or you picked the second box and then the first ball. All these things are equally likely to have occurred with equal probability, and in two cases you picked the first box, so it's two thirds.
>>27653192
It is so fing easy:
The it is already predetermined that you got either box a or b since you cant get even one gold ball from box c.
So you can ignore box c.
So the the probability is 0.5
50%
Right?
Or am I missing something?
>>27655481
there is only 1 (one) way to pick a gold ball that is in a box with another gold ball (out of 2 (two) boxes)
1/2 = 0.5
you don't get to choose which box you select the second ball from.
>>27655539
drawing the first gold ball is already guarateed so the box with two silver balls is totally irrelevant its just a red herring, You think women shouldn't have the freedom to be with who they want the question is the probability of drawing two gold balls which as there is only one box where this is possible and only two boxes factor into the question the answer is obviously a 50/50 chance
>>27653192
To all fags, i thinked it would be logically 1/2. Then i done a prop tree.
2/3.
Its 1/2 about boxes, not about balls!
>>27655659
Yeah you're right, you're not missing anything, people on here are just retarded about how you determine probabilities
>>27655584
Here's an even easier to understand version.
2/3.
But that seems so totally intuitive I'm going to assume it's wrong.
>>27655726
it is wrong.
the answer is 50%, the question is the probability of your second ball being gold, not the probability of both balls being gold
you have already gotten a gold ball so your next ball will only be a silver or a gold
its 50/50, youre over thinking it
>>27655679
I never claimed to choose which box I selected the second ball from.
There are three different gold balls you can pick first, and of those three balls, two of them are in a box with another gold ball.
2/3 = 0.666666...
Here are my thoughts on the matter.
>>27655625
they aren't equally likely because you aren't selecting the first box twice out of every three events.
you only know its 2/3 after the fact that you pick a random box. you can't do anything with this information. you picked 1 of 2 boxes and essentially you're pulling out whatever is in that box, knowing at least one of them will be gold. if you could switch boxes after pulling out a gold ball, and you again randomly selected, 2/3 of the balls will be gold.
>>27655758
the question is
>What is the probability the NEXT ball you take from the same box will also be gold?
not
>what is the probability of both balls being gold
>>27655757
Except that there are two gold balls in one box, and you could have picked either of them.
Holy fuck you guys are bad at shit.
>>27655832
I'm sensing an ambiguity:
My assumption is that the first ball is not placed back into the box when the next ball is drawn.
In that case, the probability of the next ball being gold is the same as the probability of both balls being gold.
Yours seems to be that the first ball is replaced before drawing the next ball.
I think we've arrived at the root of the debate.
>>27655817
you pick a box and it has a gold ball in it, this takes place before the question
then you take a ball from the exact same box
it is 50/50 that said next ball will be gold
you have the correct answer for the wrong question
>>27655757
But if you got a gold ball to begin with you most likely picked from the first box, therefore your second ball is more likely to be gold also.
>>27655757
But you have 2 more gold balls and only one silver. Try to be logic please.
>>27655839
irrelevant the next ball in that box will be gold
the next ball in the other box will be silver
this is all you need factor into the equation as the question is regarding the next ball only, not both balls
>>27655758
it's 0.5
see >>27655817
you can't pick three different balls because you already selected a set of two. the probability of events happening is split by the decision to select box 1 or box 2. the gold ball you pull out is from box 1 or box 2. you already pulled it out, the decision has already been made. the only way you can get 2/3 is if someone told you that box 1 has at least one gold ball and you then were asked which box you will choose. 2 out of 3 times selecting box 1 will give you two gold balls. but you do not know that until after the selection
>>27655855
It isn't, because the fact that you've already picked a ball is information in itself that changes the probability.
If you've already gotten a gold ball, then the most likely box you've picked from is the one with only gold balls in it.
>>27655855
Turns out I was wrong.
Whether or not you put the first ball back doesn't change the answer, it's still 2/3.
You already picked a gold ball, SO:
There is gonna be a 100% chance of the ball being silver in one box. There is a 100% chance of the ball being gold in the other.
You picked from one of those boxes, so there is a 100% chance the ball will be EITHER gold OR silver. 100% divided by TWO scenarios = 50%.
Something like that.
>>27655855
no, my way assumes you remove the ball from the box which leaves you with a 50/50 chance
>>27655935
Actually I saved over the wrong file, if you put the balls back each time you get this, which makes sense.
Look! I can code too!
It's all about the logic you put behind it.
50% I'd my guess mang.
>>27655855
The root of the debate are autists that try to use mathematical formulas when the problem doesn't meet the requirements instead of logic.
>>27656000
Here is the code
>>>/g/53884465
>>27655889
You know you've chosen a gold ball. This ball is either ball 1 from box 1, ball 2 from box 1, or ball 1 from box 2. Each of these things is equally likely, so the probability that you chose box 1 is 2/3, so the probability the next ball is gold is 2/3.
Assuming a b and c as the outcomes and g and s as gold and silver
Pr(AIG)= Pr(A^G)/Pr(G)
Pr(A^G)=Pr(A)= 1/3
This is 1/2 u autists:
Pr(G) = Pr(GIA)Pr(A)+Pr(G|B)Pr(B)+Pr(G|C)Pr(C)=1/3*1/2+1/3*1+1/3*0=1/2
But Pr(AIG)= Pr(A^G)/Pr(G)
So answer is 1/3/1/2=2/3
Argue to the maths
>>27656055
you don't choose balls you choose boxes
>>27655944
Except in 2/3 cases you picked the first box.
It has two possible gold balls to pick from, the other only has one. There's three possible situations.
You choose ball A first, then choose ball B second.
You choose ball B first, then choose ball A second.
You choose ball C first, then don't get a gold ball on the next try.
2 of those 3 instances result in getting a gold ball on the second try - hence 2/3. It isn't a question of which box having two gold balls, it's a question of after having already gotten a gold ball what's the probability of picking another from the same box.
>>27656000
Your logic doesn't follow the problem at all though.
Your logic would be written as:
There are 3 boxes. Each box contains 2 balls.
You pick a box at random.
The box contains at least one gold ball.
You remove one gold ball from the box..
What is the probability that the remaining ball is gold?
>>27656070
And one of those boxes has 2 gold balls in it. So if you got a gold ball on the first try it was probably that one.
>>27656076
except in 1/2 cases you picked the first box.
you don't choose any balls at all.
>>27656099
>you put your hand in and take a ball from that box at random
What is unclear about this?
>>27656058
There's only two outcomes.
You pick a box at random, not a gold ball at random.
50%
