+561 John has five children. What is the probability that at least half of them are girls? (We can assume a boy is equally likely to be born as is a girl, and vice-versa.)
Well, obiously you can't have 2 1/5 children. So the probability that John has 3 girls and 2 boys is:
((3 + 2)!)/(3! 2! 2^(3 + 2)) = 5/16 ≈ 0.3125 ≈ 1/3.2
(assuming children are independent and male and female are equally likely)
+118687 Arnolde1234, do you realize how rude it sounds to say "Incorrect" just like that?
Guest one has attempted your question and you need to be polite.
You should say something like
"Thanks guest, I don't think that is quite right because ......." you put something in for the dots.
Also, if you already know the answer and it is just an interest question then you should state this in your question.
+356 In all cases, at least half of John's kids will be boys or at least half will be girls. Furthermore, since John has an odd number of children, these conditions are mutually exclusive--that is, they are never true at the same time. Since a boy is equally likely to be born as is a girl, our answer is therefore 1/2.
