My Three SonsProbability puzzles require you to weigh all the possibilities and pick the most likely outcome.
Mrs. Mathemagican has three children. If AT LEAST one of her children is a boy, what is the probability that she has three sons?
AnswerThe probability of her having three sons is 1/7 .
Given that she has at least one boy, then there are seven equally likely outcomes for her three children: BBB, BBG, BGB, GBB, GBG, GGB, and BGG. The only one of the 8 total possible outcomes that you can rule out is GGG. Hence, the probability of three boys is 1/7.
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