Hi. I have just read the question and then read some of the forum explainations
(only some of them). Many people are getting themselves tangled up.
A couple have two kids, one of them is a girl.
Assume safely that the probability of each gender is 1/2.
What is the probability that the other kid is also a girl?
A lot of respondents are adding information that is not in the question.
Many talk about biological chances of a second child being this or that.
This is immaterial. The question gives the parameters.
Each birth has a 1/2 (or 50/50) chance of being a girl or boy.
Second. It does not state (or even imply) that the girl is first (or second) born.
It merely states 2 kids and one is a girl.
Within the framework of the question, the girl is not part of the question (she is a red herring).
The question is; what is the chance of the other (not necessarily the second) kid being a girl.
As we are told that (for this question) the chance of any birth being 50/50, then the answer is a 50% chance of a girl.
The girl/boy, boy/girl argument is mute, because we are not told order of birth, nor are we asked to infer order of birth.
So the girl/boy, boy/girl options are, in fact, only one option.
Therefore the options are two girls or one of each.
And this is purely a 50/50 proposition.
I hope this explanation helps sort out the confusion.
