Family enigma
Algebra
Level
2
Sarah's brother Danny has one more brother than he has sisters. How many more brothers than sisters does Sarah have?
The answer is 3.
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1 solution
Let Danny has s sisters and b brothers. Then b = s + 1 . Now Danny's sister Sarah has b + 1 brothers including Danny and s − 1 sister excluding herself. Therefore, Sarah has ( b + 1 ) − ( s − 1 ) = b − s + 2 = 1 + 2 = 3 more brothers than sisters.