Here's a little riddle that ought to make you think..
If a family has two children and the older child is a boy, there is a 50 percent chance the family will have two boys.
So the four possibilities are: (older, younger)
(b:g) (g:g)
(b:b) (g:b)
We know that the older is a boy, so that only leaves two outcomes, perfectly explaining why there is a 50% chance of having two boys.
But say you didn't know whether the boy was older or younger, that would only eliminate the g:g possibility, leaving three others. So the odds of a b:b are 1/3.
So how can the age of the boy determine the chance of the other child being a boy or a girl?
If a family has two children and the older child is a boy, there is a 50 percent chance the family will have two boys.
So the four possibilities are: (older, younger)
(b:g) (g:g)
(b:b) (g:b)
We know that the older is a boy, so that only leaves two outcomes, perfectly explaining why there is a 50% chance of having two boys.
But say you didn't know whether the boy was older or younger, that would only eliminate the g:g possibility, leaving three others. So the odds of a b:b are 1/3.
So how can the age of the boy determine the chance of the other child being a boy or a girl?



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