CA Foundation · Quantitative Aptitude · Blood Relations
P says, "I have as many brothers as sisters." P's sister Q says, "I have twice as many brothers as sisters." If P and Q are children of the same parents, how many children are there in the family?
There are 7 children. P must be a boy, so boys equal girls plus one, while Q's statement gives boys equal twice the girls minus two. Solving these gives 3 girls and 4 boys, which makes 7 children.
- A5
- B6
- C7Correct
- D4
Explanation
Let there be b boys and g girls. If P is a boy, then b-1 = g. Q is a girl, so b = 2(g-1). Substituting gives g+1 = 2g-2, so g = 3 and b = 4. The total is 7. Taking P as a girl would give g-1 = b, which together with b = 2(g-1) forces g = 1, and then Q could not exist as a separate sister. So P is a boy.
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One question tells you little. A timed set on Blood Relations shows your real accuracy, how long you take and where you lose marks.
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