Multiple choice general knowledge math & puzzles

A boy has as many sisters as brothers and his sister has half as many sisters than brothers. How many boys and girls are in the family?

  1. 4 & 3

  2. 4 & 4

  3. 3 & 3

  4. 3 & 4
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Let boys = b, girls = g. Any boy has g sisters and (b-1) brothers, so g = b-1. Any girl has (g-1) sisters and b brothers, and she has half as many sisters as brothers: g-1 = b/2. Substituting g = b-1: (b-1)-1 = b/2, giving 2b-4 = b, so b = 4, then g = 3. Check: Boy has 3 sisters and 3 brothers (equal). Girl has 2 sisters and 4 brothers (2 is half of 4). Option A (4 boys, 3 girls) is correct.

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