So let's take a look at the following diagram. The following pun and square to basically calculate what the probabilities are, first we actually have to apply the product rule. So let's say this is event number one and let's suppose that we have so this is our boy and girl and then we have boy and a girl. So once again we have a probability of one half here, a probability of one, one half here. Sorry if it's sloppy. So we have one half here, one half here.