Assume that each born child is equally likely to be a boy or a girl . If a family has two children, what is the conditional probability that both are girls given that  the youngest is a girl.     

Explanation

To solve the problem, we need to find the conditional probability that both children are girls given that the youngest child is a girl.

### Step-by-Step Solution:

1. **Identify Possible Outcomes**:
When a family has two children, the possible combinations of genders are:
- Boy (B) and Boy (B): BB
- Boy (B) and Girl (G): BG
...