So let's say child number one is normal. Well, the probability is 50%, as we saw in case A. So we saw that there is a 50% likelihood that the child is colorblind, which means it is a 50% likelihood that the child is normal. So child one is normal with a 50% likelihood and this is equivalent to 0.5. Now, what about child number two? Well, likewise there's a 50% likelihood by the same exact reasoning that child number two is normal.