Question

It is commonly assumed that babies are equally likely to come as either a boy or a girl. This is not true. Actually, about 51.3% of all babies are boys. If a family has two children (not twins), what is the probability they have one boy and one girl?

Answer 1

49.97% probability they have one boy and one girl.

Explanation:

For each children, we have these following probabilities

0.513 = 51.3% probability of being a boy

1-0.513 = 0.487 = 48.7% probability of being a girl

If a family has two children (not twins), what is the probability they have one boy and one girl?

It can be either a boy and then a girl, or a girl than a boy.

So

`P = 2*0.513*0.487 = 0.4997`

49.97% probability they have one boy and one girl.