A family has two children.If all outcomes are equally likely,what is the probability that they have a boy and a girl?

A) 1/4
B) 1/2
C) 1/3
D) 2/3
E) 1

The possible outcomes for two children are BB, BG, GB, and GG (where B represents a boy and G represents a girl). Each of these outcomes is equally likely.
Out of these four outcomes, only one outcome has one boy and one girl (BG and GB are considered the same outcome since order doesn't matter). Therefore, the probability of having a boy and a girl is 1/2 or 50%.