Ellen plans to have two children but doesn't know if they are boy-boy, girl-girl, or boy-girl. What is the probability that she will have two girls?

0.25

0.5

0.75

1.00

I know the answer is. 25 but how do you get that answer?

There are four ways in which the genders of the children may be arranged. In addition to those already given above is girl-boy. Among the four, there is only girl-girl. Thus, the probability that Ellen will have two girls is 1/4 or 0.25.

You can have a girlboy boygirl boyboy girlgirl and one of those answers iss out of 4 and 1/4 is. 25