Riddles

[Fort Fun Indiana]

First one:

You meet a girl. She tells you she has one sibling. What are the odds her sibling is also a girl?

 

[Toddsterpatriot]

50/50

 

[OldLady]

First one:

You meet a girl. She tells you she has one sibling. What are the odds her sibling is also a girl?

48%?
But that's not a riddle.

 

[Fort Fun Indiana]

50/50

No.

 

[Fort Fun Indiana]

First one:

You meet a girl. She tells you she has one sibling. What are the odds her sibling is also a girl?

48%?

No. And yes, it's a riddle. You have to approach it correctly to get the correct answer.

 

[OldLady]

This calls for Treeshepherd.

 

[depotoo]

Boy or Girl paradox - Wikipedia

 

[Fort Fun Indiana]

Boy or Girl paradox - Wikipedia

depotoo had to look it up. He is awarded zero points. Let's see if someone can get it on their own.

 

[Toddsterpatriot]

50/50

No.

Yes.

 

[OldLady]

Boy or Girl paradox - Wikipedia

I was just looking at that, but the answer is still 1/2.

Oh lord, is this going to be another "The answer is 1" thread?

 

[OldLady]

Boy or Girl paradox - Wikipedia

depotoo had to look it up. He is awarded zero points. Let's see if someone can get it on their own.

Maybe I didn't read far enough, but my article didn't have an answer.

 

[depotoo]

Boy or Girl paradox - Wikipedia

depotoo had to look it up. He is awarded zero points. Let's see if someone can get it on their own.

I had heard it before.

 

[Fort Fun Indiana]

50/50

No.

Yes.

No, sorry. I will explain, eventually.

 

[Fort Fun Indiana]

Boy or Girl paradox - Wikipedia

I was just looking at that, but the answer is still 1/2.

Oh lord, is this going to be another "The answer is 1" thread?

No.

 

[Crepitus]

50/50 I would think

 

[OldLady]

50/50

No.

Yes.

No, sorry. I will explain, eventually.

You need to move along with the answer. We're going to die of old age. Anyone who wants to play can try the next riddle.

 

[Fort Fun Indiana]

50/50

No.

Yes.

No, sorry. I will explain, eventually.

You need to move along with the answer. We're going to die of old age. Anyone who wants to play can try the next riddle.

Ha! Okay, will do.

 

[Toddsterpatriot]

50/50

No.

Yes.

No, sorry. I will explain, eventually.

Unless your explanation is 50/50, you're wrong.

 

[Fort Fun Indiana]

OldLady

So, the answer is 1/3. (depotoo knew this already)

Why?

There are four equally likely possibilities (in this case, permutations) for two siblings, oldest listed first:

BB
BG
GB
GG

We have met one sibling, and she is a girl. So now, there exist three equally likely possibilities:

BG
GB
GG

As these are equally likely, the probability of each possible permutation is now 1/3. So, the probability that the other sibling is also a girl is 1/3.

Had you been given the information of whether the girl we met was the older or younger sibling, the answer would have been 1/2.

 

[Fort Fun Indiana]

50/50 I would think

Right, that's the immediately intuitive answer. But it is not correct.