SOLUTION: Alice and Bill are planning to have three children. (Assume that it is equally likely for a boy or a girl to be born.) What is the probability that at least one will be a girl?

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Question 991112: Alice and Bill are planning to have three children. (Assume that it is equally likely for a boy or a girl to be born.)
What is the probability that at least one will be a girl?

Answer by Fombitz(32388) About Me  (Show Source):
You can put this solution on YOUR website!
Let's do it backwards.
Assume none of them are girls, so they're all boys.
P%28BBB%29=%281%2F2%29%281%2F2%29%281%2F2%29=1%2F8
So then the complement, at least one girl, would be,
P=1-1%2F8
P=7%2F8