Scenario 1. An expectant mother has been told she is giving birth to twins. She wants to have a daughter, but does not mind what sex her other twin is. Question 1. What is the probability that at least one of the twins is a girl? Scenario 2. The doctor asks her whether she wants to find out the sex of her twins. She tells the doctor that she only wants to know whether she is having a girl, and the doctor confirms that she is. The doctor does not reveal the sex of the other child. Question 2. Given that she knows one of the twins is a girl, what is the probability of the other one also being a girl? NB: Assume that each baby has an equal chance of being either a boy or a girl.