Data sufficiency to establish a sibling relationship
Question
Consider the Question and two Statements given below: Question: Is Z brother of X? Statement-1: X is a brother of Y and Y is a brother of Z. Statement-2: X, Y and Z are siblings. Which one of the following is correct in respect of the Question and the Statements?
Options
Statement-1 alone is sufficient to answer the Question
Statement-2 alone is sufficient to answer the Question
Both Statement-1 and Statement-2 are sufficient to answer the Question
Both Statement-1 and Statement-2 are not sufficient to answer the Question
Explanation
To definitively answer "Is Z the brother of X?", we must know two things: that they are siblings, and that Z is male.
Statement 1 establishes the chain: X (male) is the sibling of Y (male), who is the sibling of Z. While this proves they are all siblings, it provides zero information about the gender of Z. Z could be a brother or a sister.
Statement 2 simply states they are siblings. Again, no gender is provided for Z.
Combining both statements yields no new data regarding Z's gender. The question remains unanswerable.
Answer: (d).
Question details
Year
2022
Paper
CSAT
Question
Q25
Section
Data Interpretation & Sufficiency
Sub-topic
Blood Relations
Type
Factual single
Difficulty
Medium
Source hint
Is Z brother of X?
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