Sadly no matter what kind of prompting that I try it fails the sisters question:
> Sally (a girl) has three brothers. Each of her brothers has two sisters. How many sisters does Sally have?
Sally (a girl) has three brothers. Each of her brothers has two sisters. How many sisters does Sally have?
Sally has two sisters. Here's the reasoning: Sally has three brothers. Each of her brothers has two sisters. Since her brothers are the ones who have two sisters each, and we know there are three brothers, we can conclude that each brother has two sisters. Therefore, there are two sisters in total (one for each brother). So, Sally has two sisters.