Seeing as this is currently breaking Facebook…

From the question

What is the probability that the other one is a male?

So it does pretty much say what you say it doesnt say

nowhere does he say “1 dog is male, whats the probability another dog is male

Its a question written in a vague manner to conceal what he wants the question to be.

Not scary at all.  If you think your solution is the answer to the riddle as posed is post 1 then it’s just wrong.

According to you. But you are wrong

I’ve got two oranges in my hands. One of them is rotten. What’s the probability the other is also rotten?

The probability of a dog being male or famale is 0.5. It doesnt matter what the dog next to it is. Its a poorly worded question.

In your orange example you use “also” as does thecquestioner in what he says is the essence but not in the actual question

I’ve got two oranges in my hands. One of them is rotten. What’s the probability the other is also rotten?

Would depend on how both had been treated, its not fixed at conception by a 50:50 ratio of sperm like gender

The probability of a dog being male or famale is 0.5. It doesnt matter what the dog next to it is. Its a poorly worded question.

🙂

No one has ever been asked to consider just one dog at a time. The bather wasn’t and the probability calculator wasn’t.

If the word also troubles you, take it out. It makes no odds. Although I accept the other orange in my example is sat next to a manky orange so if it sits there too long whilst we procrastinate it doesn’t matter and it’ll be rotten too regardless.

So why add the word “also” to your orange example?  The op’s posted question was poorly (or well) worded by the questioner.

So why add the word “also” to your orange example?

Ok

I’ve got two oranges in my hands. One of them is rotten. What’s the probability the other is rotten?

Aside from cross contamination, what is the answer?

No one has ever been considered to think about just one dog at a time. The bather wasn’t

Alas, we’ll never know. She could have picked up the first dog by the scruff (phone cupped under chin whilst cursing her husband for calling her when he knows she’s bathing the bloody dogs) and seen its penis. No need to check the second dog then.

I’ve got two oranges in my hands. One of them is rotten. What’s the probability the other is rotten?

No idea, it depends on a huge number of other factors

According to you. But you are wrong

One of us clearly doesn’t understand the difference between

“What is the probability that the other one is male”

And “what is the chance that there are two boys”

And I can assure you that it fundamentally changes both the logic and the math.

I’ve checked the probabilities and it 100% isn’t me.

Alas, we’ll never know. She could have picked up the first dog by the scruff (phone cupped under chin whilst cursing her husband for calling her when he knows she’s bathing the bloody dogs) and saw its penis. No need to check the second dog then.

Agreed. As she was not asked to check if both were male she had enough information after the first inspection that she could stop fiddling with the dogs and still answer the question. But the dog she picked up was random. If she had been asked to check if ‘Rover’ was male then the question was is ‘Fido’ male I’d have some truck with the 50%ers. But she wasn’t.

Have a think about this one then…

“I have two children. One is a boy born on a Tuesday. What is the probability I have two boys?”

“Your first impression is: what does Tuesday have to do with it?” says Gary, “And you might think that it doesn’t. But in fact Tuesday has everything to do with it. And the actual answer to the problem is 13/27.”

It’s the same, but MOAR.

http://news.bbc.co.uk/1/hi/programmes/more_or_less/8735812.

WARNING: contains actual maths. It is correct, and extremely carefully worded. With these things (idealised probability puzzles) the wording is everything, it dictates the known, unknown and the answers.

Real word “what ifs” don’t get a look in!

I’ve checked the probabilities and it 100% isn’t me.

I’d give that calculator of yours a bash – it seems to be on the wonk.

I’ve got two oranges in my hands. One of them is rotten. What’s the probability the other is rotten?

Aside from cross contamination, what is the answer?

Before I answer which one was closest to the bananas in the fruit bowl?

Before I answer which one was closest to the bananas in the fruit bowl?

They were arranged in an amusing two oranges and one banana configuration. The bowl however was on a treadmill. Going backwards. On a Tuesday.

Or to satisfy him up there…What is probability that both of the oranges I am holding are rotten? Because that is clearly a totally different answer.

They were arranged in an amusing two oranges and one banana configuration. The bowl however was on a treadmill. Going backwards. On a Tuesday.

Which way was the wind blowing the ethylene?

I understand that there are 4 possibilities before the wife is spoken to.

But why does her answer not rule out 2 options instead of one? Once she has looked at at least one dog, be it male or female then female-female is ruled out we all agree as she says that there is a boy, but surely male-female OR female-male is also ruled out because the sex of the dog she is looking at is known (even though we and the prospective purchaser don’t know it). Male-female AND female-male can no longer both be possibilities.

I understand that there are 4 possibilities before the wife is spoken to.

But why does her answer not rule out 2 options instead of one? Once she has looked at at least one dog, be it male or female then female-female is ruled out we all agree as she says that there is a boy, but surely male-female OR female-male is also ruled out because the sex of the dog she is looking at is known (even though we and the prospective purchaser don’t know it). Male-female AND female-male can no longer both be possibilities.

If you appreciate there were 4 possibilities before the phone call you are nearly there. So before the call there was a 25% chance both were males, 25% both females and 50% there was one of each. All the information gained over the phone allowed you to do is knock out one of the 4 options. So MF and FM are still on the table (along with MM).

But FM=MF in this case as it doesn’t matter which of those combos occur.

Another vote for this being the Monty Hall problem with some Chinese whispers added which inadvertently change it to something else.

Not Monty Hall. There are no doors you have to choose from. You get what is behind both doors.

You get what is behind both doors.

You do. Only snag for you 50%ers is that all you know is that there is a male beagle behind one of the doors. Neither door has yet been opened.

if i back 2 football teams to get into the next round of the FA Cup,

the outcomes are WW, WL,  LL (i guess others would say WW, WL, LW, LL)

lets say the early game i get the result and win, as result one is known then its 50/50 on result two to win overall..

hence a bookie may be willing to offer a cashout

it all depends if you see the two items as related. when you know the outcome of one result in a pair, then the next result is always 50/50, but overall the probability is not 50/50..

ah, im back nice and refreshed after a good nights sleep and ready to fight the good fight in the name of common sense……. which may be the problem here, people arent using good old common sense and reading the question for what it is. RTFQ!

But the way it is written it doesn’t matter what dog A or dog B is.  All that is necessary is that one of dog A and dog B is male and what are the odds that dog A and B are both male.  Since we know one of dog A and B is male then it’s 1/2 that the other of the pair is male.

……is all that matters here.  youre complicating matters by comparing this question to opening doors, tossing coins…. why put yourself through the pain?

RTFQ!  nowhere does it say the woman replied that yes one is male but im not telling you which yet youve got to work out the likelihood of only dog B being male.

also the question doesnt say ‘according to the laws of maffurmatics give the right answer….’.  it just says……

A man sees a sign in a window advertising two Beagle puppies for sale. He goes in and tells the shopkeeper he will only take the puppies if there’s at least one boy.

The shopkeeper phones his wife who is bathing the dogs and asks her if there’s at least one boy. She says yes.

What is the chance there are two boys?

theres at least one boy, doesnt matter if its A or B, whether she looked at one dog or two to get there, she could have said yes theyre both boys but didnt, she just said theres at least one boy.  so options left are theyre both boys, or theres one boy and one girl.

again, doesnt matter if the BG combo is A (male) and B (female) or t’other way round.  MF or FM, doesnt matter one jot according to how the question is worded.  those who dont say 50% are adding or taking away info that isnt given or required.  RTFQ!

I understand that there are 4 possibilities before the wife is spoken to.

But why does her answer not rule out 2 options instead of one?

Because observation does not change the likelihood.

There are four equally likely permutations before the wife is spoken to.  This doesn’t magically change with the addition of extra information.  We are told  that at least one is male.

If both are male, is at least one of them male?  Yes.

If one is male and the other female, is at least one of them male?  Yes.

If one is female and the other male, is at least one of them male?  Yes.

If both are female, is at least one of them male?  No.

I applaud your passion sadexpunk – but you are still wrong 🙂

So, How many were Heagles and how many were Sheagles?

she just said theres at least one boy.  so options left are theyre both boys, or theres one boy and one girl.

That is correct.  However, what you’re missing / ignoring is that the probability of those two options are not equal.  It’s twice as likely to be the latter than the former.

those who dont say 50% are adding or taking away info that isnt given or required.

Quite the opposite.  Those who those who do say 50% are adding or taking away info that isn’t given or required.  They’re prescribing “one is male” to an individual dog and then going “well, the other one must be male or female then.”  You can’t do that, it ignores the notion that the one that is male might be the other one.

If nothing else at least this thread explains Brexit

In a weird way making the question a tiny bit more complicated might help some of you to understand…

There are now three puppies being bathed. The wife tells her husband that at least one of the puppies is male. Do the 50%ers still think the chance of all 3 being male is 50%?

Take is one stage further (stupider). There are 100 puppies in the bath. The wife tells her husband at least one of the puppies is male. Do the 50%ers still think the chance of all 100 being male is 50%?

If you don’t, explain why not, give the correct answer and show your workings (on the 3 puppies scenario as the 100 puppies version might take a while) It’s the same principle.

If nothing else at least this thread explains Brexit

Indeed and not (necessarily) in a negative way. Two groups facing the same set of facts and both absolutely convinced they know the answer based on what is in front of them. The fact that one of the two groups would probably fail their GCSE paper if they took it tomorrow is neither here or there 😉

That is correct.  However, what you’re missing / ignoring is that the probability of those two options are not equal.  It’s twice as likely to be the latter than the former.

herein maybe lies the crux of the issue if we can bash this out.  i say its not twice as likely, its the same.  and sorry convert, much as im willing to look at other ways around this, i cant even think about 3 or 100 dogs as thats not what we’re faced with.  im only interested in this one question and how its worded 🙂

sorry convert, much as im willing to look at other ways around this, i cant even think about 3 or 100 dogs as thats not what we’re faced with.  im only interested in this one question and how its worded

Promise it will help. Get the answer to the 3 dog question right, then explain why you are not using the same method to the 2 dogs question. It’ll be cathartic.

@convert can you understand why people with one result in hand then assume its 50/50 on the second bet..

google “tossing a coin twice in a row odds” may help

You know from experience that if you flip a coin twice, sometimes you get tails twice in a row. That is because each time you flip the coin, the odds remain 1/2; the two flips are independent of each other. The odds of getting tails twice in a row are 1/2 * 1/2 = 1/4. So 25% of the time you’ll get heads twice in a row.

but as the majority of 50/50 comments state, you know the result of one hence, the next result is independent

hence 50/50 you can only have heads or tails.., the probability you get it is 1/4

if i was in the pub i think i’d go for 2 heads in 3 tossers, better odds

herein maybe lies the crux of the issue if we can bash this out.  i say its not twice as likely, its the same.

Try this: Before we know anything other than there being two dogs the probabilities are FF =1/4, MF = 1/2, MM = 1/4. MF is twice as likely as MM. Do you agree with that?

Now, probably the tricky bit. The only thing we are told is that “there is at least one boy” and with that information all we can do is exclude option 1, it isn’t FF. MF is still twice as likely as MM so the odds are now MF = 2/3, MM = 1/3

i can see your way of thinking cougar (or i think i can anyway), youre thinking we’ve still got two dogs to play with, whereas im saying we’ve got one.  as soon as the wife says at least ones male, then its gone, out of the running, its deceased, it is no more, its a dead dog.

another way of wording it……whats the chances of the other one now being the same as that male one 😉

herein maybe lies the crux of the issue if we can bash this out.  i say its not twice as likely, its the same.

If the wife was busy and didn’t answer the phone do you agree that at that point the chance of one male and one female was twice as likely as both male?