[FizMan]

I just wrote my own computer program.


IF you choose a random child to open the door then it's an outcome of 50%

IF you choose a girl to answer the door (I still say the question provides that as a given), then the outcome is 33%


But I don't know... I honestly don't agree with your teacher's logic... yes I agree that the gender of one doesn't influence the gender of the second... but she seems to ignore the fact that there are twice as many families with a boy and a girl than there are with two girls. The gender of the second kid isn't generated when you meet them (i.e. flip the coin); it's already been made... and fact is twice as many "tails" get flipped than "heads."


Also, why does opening the door and getting a girl eliminate 500 doors? Shouldn't it only eliminate 250 doors (b/b) as even in the b/g & g/b families, either one could have answered the door? And wouldn't that leave 250 doors with GG and 500 with some combination of GB?