2009-03-13, 04:18 AM
Peoples, go back to page 3. Follow the link, and learn to read. Its 33%.
One of them is a boy. For the other to also be a boy you'd need the scenario BB.
Out of four choices
BB
GB
BG
GG <- this one is gone automatically.
GB and BG are not the same since you don't know which kid is which. You're not allowed to assume that the OLDER kid is the boy (GB) or that the YOUNGER kid is the boy (BG).
If, and only if, you're told which kid is the boy, then it turns out to be 50%.
Ex. If you know the older kid is the boy
BB
GB
BG <- goes away
GG <-goes away
50% chance of the other kid being a boy too
Same applies if you know the younger child is a boy.
BUT you dont know that >>
Thus GB & BG have to be treated separately.
Case in point, three posibilities that you are ALL overly complicating:
BB
GB
BG
1/3 chance of 1 kid being a boy AND the other kid being a boy (BB)
Done. nothing else. no more. gtfo with intuition, it doesn't always work. There's a TON more math concepts that intuition will fail with. And if you guys aren't able to look past your first instinct you will fail upper division math classes in college. Take this from a math major.
One of them is a boy. For the other to also be a boy you'd need the scenario BB.
Out of four choices
BB
GB
BG
GG <- this one is gone automatically.
GB and BG are not the same since you don't know which kid is which. You're not allowed to assume that the OLDER kid is the boy (GB) or that the YOUNGER kid is the boy (BG).
If, and only if, you're told which kid is the boy, then it turns out to be 50%.
Ex. If you know the older kid is the boy
BB
GB
BG <- goes away
GG <-goes away
50% chance of the other kid being a boy too
Same applies if you know the younger child is a boy.
BUT you dont know that >>
Thus GB & BG have to be treated separately.
Case in point, three posibilities that you are ALL overly complicating:
BB
GB
BG
1/3 chance of 1 kid being a boy AND the other kid being a boy (BB)
Done. nothing else. no more. gtfo with intuition, it doesn't always work. There's a TON more math concepts that intuition will fail with. And if you guys aren't able to look past your first instinct you will fail upper division math classes in college. Take this from a math major.