xAI: Grok 4
Based on the details in the riddle, Sally has exactly 1 sister.
Quick Explanation
- Sally (a girl) has 3 brothers. That's straightforward.
- Each of those brothers has exactly 2 sisters (female siblings).
- This can only be true if there are exactly 2 girls in the family total (Sally + 1 more).
- Therefore, Sally herself must have exactly 1 sister (the other girl).
Family Breakdown
- Boys: 3 total (Sally's brothers).
- Girls: 2 total (Sally + 1 sister).
- From any brother's perspective: He has 2 brothers (male siblings) and 2 sisters (female siblings). This matches the riddle exactly.
- From Sally's perspective: She has 3 brothers (male siblings) and 1 sister (female sibling). Again, this matches.
If there were more (or fewer) than 2 girls total, the "each brother has 2 sisters" part of the riddle couldn't possibly be true. No other interpretation fits the facts as stated.
Common Mistake to Avoid
Some people misread this type of riddle and try to multiply things (e.g., "3 brothers × 2 sisters each = 6 sisters"), but that's incorrect because it massively overcounts the same sisters. There's no need for math here beyond basic counting of boys vs. girls. The family simply has 3 boys and 2 girls, as explained above.
If this doesn't match what you think the answer is, or if there's more context I'm missing, feel free to reply!