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I have a short question from a homework. given a family with 3 children, the sexes of which are unknown: if the eldest child is a boy and there is at least one other boy, then what is the probability one child is a girl?

To me it seems obvious that there are at least two boys from this info, then either there are 3 boys or 2 boys and 1 girl, so the probability one child is a girl is 0.5. Is this method correct?

Thanks,

JB

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# Homework Help: Short Question

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