Logic Puzzle

Let's go step by step.

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Step 1: Identify Sally's family from her point of view

Sally is a girl.
She has 3 brothers.
So there are 3 boys in the family and Sally (1 girl so far).

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Step 2: Consider the statement "Each brother has 2 sisters"

From a brother's perspective, his sisters are all the girls in the family except himself (since he’s a boy).
If each brother has 2 sisters, that means there are 2 girls in the family total, from the brother’s point of view.

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Step 3: Determine the number of girls

We already know Sally is one of these girls.
If there are 2 girls total, then Sally has 1 sister.

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Step 4: Conclusion

Sally has 1 sister.

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