The Boy or Girl Conditional Probability Problem

Hard

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A family has two children. You learn that at least one of them is a boy. What is the probability that both children are boys? Assume each child is equally likely to be a boy or a girl, and the genders are independent.

Multiple Choice

1/2, because the other child is equally likely to be a boy or girl 1/4, because each child has a 1/2 chance of being a boy 1/3, because of the three equally likely outcomes with at least one boy, only one has two boys 2/3, because knowing one is a boy makes it more likely the other is too

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The Boy or Girl Conditional Probability Problem

Multiple Choice

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