Multiple choice general knowledge math & puzzles

If we encounter someone with exactly two children, given that at least one of them is a boy, what is the probability that both of her children are boys?

  1. 1/3

  2. 1/2

  3. 1/4

  4. 3/4
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A Correct answer
Explanation

With two children, equally likely possibilities are BB, BG, GB, GG. Given 'at least one boy', GG is eliminated. Remaining: BB, BG, GB (3 cases). Only BB has both boys, so probability = 1/3.

AI explanation

With two children there are four equally likely combinations: BB, BG, GB, GG. Knowing at least one child is a boy eliminates GG, leaving three equally likely outcomes: BB, BG, GB. Only one of those three, BB, has both children as boys, giving a probability of 1/3. This is different from asking about a specific, already-identified child, which would give 1/2.

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