You see that here, doubles one, doubles two, doubles three, doubles four. Well, given that, what's the probability that the four-sided die is a four? Well, that means that's one of these four outcomes where it's a double fours right over here. All right, what is the probability of A and B? The probability that Erica rolls doubles and the second die is four. So this means both A and B happened. Well, let's look at this.