Poll: A little math problem

[Fud]

I was looking around on the internet, and I found something about Marilyn vos Savant. When I was reading about it I saw an interesting math problem. This was taken directly from Wikipedia, so I'm not certain about its accuracy in wording:

A shopkeeper says she has two new baby beagles to show you, but she doesn't know whether they're male, female, or a pair. You tell her that you want only a male, and she telephones the fellow who's giving them a bath. "Is at least one a male?" she asks him. "Yes!" she informs you with a smile. What is the probability that the other one is a male?

Please answer the poll before reading on.

I think Vos Savant said that it was a 1/3 chance, although the Wikipedia article wasn't very clear about it. However, I though it was interesting, and since this is seems to be a smart forum, I thought I'd ask it here.

 

[Jazzyluv]

well, if their is only 2 beagles, we know one is a male, then thier is a 50/50 chance of the other being male or female....

 

[OuroborosChoked]

Does it matter what gender the other dog is?

 

[Fire Daemon]

The chance that both dogs are male is 25%. Flip two coins, whats the chance of both being heads or both being tales? 25% with a 50% that one will be heads one will be tails.

The same thing applies here. I think. I might have read the question wrong.

 

[Noamuth]

Okay. I feel stupid, but the 75% was jumping out at me.

Just a little flag going up in my brain somewhere. Either that, or early onset dementia.

 

[Captain Wes]

basically you're saying forget the dog we know is male, what's the other one? thusly it's 50/50 it can be male or it can be female.

 

[TheGhostOfSin]

Should we factor in the chance that it could be a hermaphrodite?

 

[Shivari]

It's a pretty basic math problem unless you're supposed to factor in what GhostOfSin suggested. Then it's just trying to be tricky.

 

[ObnoxiousTwat]

75% works because we know one is male and the chance the other is male is half of that (1\2 of 25% + 50% = 75%)

I thought about this way too much.

 

[Shivari]

75% works because we know one is male and the chance the other is male is half of that (1\2 of 25% + 50% = 75%)

I thought about this way too much.

No, it would be 50% because it's a separate beagle, the other one being male would have no effect on it.

 

[Fire Daemon]

75% works because we know one is male and the chance the other is male is half of that (1\2 of 25% + 50% = 75%)

I thought about this way too much.

Thats not the way probability works.

To find the probability of two things you must multiply them. The chance of one dog being male is 50% or 1/2.

1/2 is 0.5. 0.5 times 0.5 is 0.25 or 25%

The probability of both dogs being males is 25%. However looking at the question it appears to be asking what the chance of one dog being male is, which is 50%. It's a strange question that can interpreted differently.

 

[Jamanticus]

Should we factor in the chance that it could be a hermaphrodite?

You just made my day, GhostOfSin- heck, you just made my week.

 

[Lord Krunk]

50%.

Okay, factor in that it's a 100% chance that one of two is that it's female, and that the question asks what the other one will be, not regarding the male one.

It has to be 50%, because no matter what, there's an even chance of being male or female.

BASIC MATHS, PEOPLE: Read the question. They throw in Red Herrings on purpose.

 

[dirtface]

Ok this is like the monty hall problem.
If atleast one is male, you have three possible situations
Beagle1 Beagle 2
Male Male
Male Female
Female Male

Of these three possible outcomes, only one of them results in the second beagle being male.
Thats where the 33% comes from...
That's the logic behind the problem, however there's also the idea of independent events... the mind boggles.

 

[Jumplion]

Should we factor in the chance that it could be a hermaphrodite?

That's exactly what I was thinking after I finished reading the question...

But it's 50%, we know one dog's a male and they're asking what's the probability of the other being male. It's not asking for the possibility of a pair or not, just if the other is male or not.

50%

I just know there's something sinister behind this.

 

[ObnoxiousTwat]

Damn you math!! Even outside of school you make me look stupid.

 

[Noamuth]

Ok this is like the monty hall problem.
If atleast one is male, you have three possible situations
Beagle1 Beagle 2
Male Male
Male Female
Female Male

Of these three possible outcomes, only one of them results in the second beagle being male.
Thats where the 33% comes from...
That's the logic behind the problem, however there's also the idea of independent events... the mind boggles.

Never thought to use the Monty Hall problem for this. Nice.

 

[Gotham Soul]

50%: It's either a male or its something else.

 

[Labyrinth]

Thing is, the gender of the second has no apparent relation to the gender of the first unless you factor in a whole shit load of biological variables which I don't really care to. As such, the two are as mutually exclusive as one coin-flip from the next. (Keep in mind that -any- series of coin results is as unlikely as any other.)

So I'll say 50%.