In a class of 18 students, 5 have a brother and 11 have a sister. There are 5 students who do not have any siblings. What is the probability that a student has a sister given that they do not have a brother?

I think the images should make sense. If not, just comment, I’ll be here. (It’s only letting me insert one image so I’ll have to exp this part) once you’ve filled the two way table in, you circle the two squares that Apple to the situation. In this case, which ones don’t have a brother? The top right and bottom right fit that bill. Then you divide the number of students that actually have a sister but the two squares (added together) that do t have a brother. So it’d be 5/10 which is .5 for an answer