Logic Puzzle

I need to work through this step-by-step.

Given information:

• Sally has 3 brothers
• Each brother has 2 sisters

Let me think about this carefully:

Since Sally is a girl, she is one of the sisters that each brother has.

If each brother has 2 sisters, and Sally is one of those sisters, then there must be 1 additional sister besides Sally.

Therefore, Sally has 1 sister.

To verify:

• Sally + 1 sister = 2 sisters total
• Each of the 3 brothers has these same 2 sisters
• This matches the given information that each brother has 2 sisters

Sally has 1 sister.