JonC

Same, using Chat GPT 4. It explained the steps without prompting, which is different from the single line answer shown in the post too. I got this…

Let’s break this down step by step:

1. Sally has 3 brothers.
2. Each of those brothers has 2 sisters.

Sally is one of those sisters for each of her 3 brothers. Therefore, the second sister that each brother has would be the same other sister.

This means that Sally has only 1 other sister, making a total of 2 sisters in the family (including Sally herself).

So, Sally has 1 sister.