Grok 3
Sally, a girl, has 3 brothers. Each of these brothers has 2 sisters. Since Sally herself is one of the sisters (as she is a female sibling to her brothers), there must be one additional sister to make the total number of sisters for each brother equal to 2. Therefore, the family consists of 2 girls (Sally and her sister) and 3 boys (Sally's brothers).
From Sally's perspective, the number of sisters she has is the number of female siblings, which is just her one sister. Thus, Sally has 1 sister.
Answer: Sally has 1 sister.






