2009-03-12, 06:49 PM
Devil's Sunrise Wrote:The thing here is that it's not harder to give birth to a male after giving birth to another. The thing is that they have already been born. Say, you give life to two children. Then the following sequences are available:
BB
BG
GB
GG
Now, what is the chance of having 1 boy and 1 girl? that's 1/2. The chance of having 2 boys are 1/4.
Now, we already know that there is a boy in this combination. That leaves the 2 girls out.
BB
BG
GB
The 1 boy 1 girl probability is now 2/3, and 2 boys are 1/3.
Read above.
And mang, I found the riddle:
Two Boys problem. Didn't know she was the one who "gave the answer" to this one though.
I understand the logic there, but once a variable is no longer random, it shouldn't be considered into the ecuation. If you flip a coin 5 times, and you know it was all the same side, you can take them out. It's the same possibility for either side on the next.
You don't know which one is, but you know it's one, and that the other is independant to the other.