SOLUTION: A couple has 7 children. What is the probability of having exactly 2 boys?

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Question 453567: A couple has 7 children. What is the probability of having exactly 2 boys?
Answer by edjones(8007) About Me  (Show Source):
You can put this solution on YOUR website!
Assume an equal likelihood of having a girl or a boy.
g=.5, b=.5
(g+b)^7
nCr=7C2=21
21g^5b^2
=.1641 the probability of having exactly 2 boys.
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Ed