Pointing to an old man, Kunal said, "His son is my son's uncle." How is the old man related to Kunal?

Appeared in: RRB Staff Nurse Kolkata-2015

Explanation

The puzzle is solved by breaking down the statement from the speaker's (Kunal's) point of view.
First, identify the relationship 'my son's uncle'. In the context of these puzzles, this refers to Kunal's brother.
The statement equates the 'old man's son' with 'Kunal's brother'.
If the old man's son is Kunal's brother, it logically follows that the old man is the father of both Kunal and his brother.

Option A: The old man is from the generation above Kunal, as he is the father of Kunal's brother. Therefore, he cannot be Kunal's brother.
Option B: The old man is Kunal's father, which is one generation above. A grandfather would be two generations above.
Option D: A brother-in-law is a relationship through marriage (e.g., spouse's brother or sister's husband). The statement describes a direct bloodline relationship.

Visual 1: Family Tree Diagram - A simple chart showing the Old Man at the top, with two sons branching down: Kunal and Kunal's Brother. A line from Kunal then leads down to Kunal's Son. An arrow can show that Kunal's Brother is the 'uncle' to Kunal's Son, clarifying the entire set of relationships.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Blood Relation Logical Reasoning as background academic context rather than a clinical decision trigger.
This question tests logical reasoning and the ability to deduce relationships from complex statements, a skill useful for problem-solving in any field.
There is no direct clinical relevance as this is a general aptitude question.
What if the statement was 'His only son is my son's uncle'? The answer would remain the same, as the core logic is unaffected. The word 'only' would just confirm Kunal has exactly one brother.

How to Approach the Question

First, identify the speaker (Kunal) and the subject (the old man).
Break the given statement into smaller, manageable parts. Start with the part that relates directly to the speaker, which is 'my son's uncle'.
Translate this part into a simpler relationship: 'my son's uncle' = 'my brother'.
Substitute this simpler relationship back into the full statement: 'His (the old man's) son is my brother.'
Analyze the resulting statement to find the final relationship: If someone's son is your brother, that someone must be your father.
Select the option that matches your conclusion.

Concept Tested & Keywords

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Practise the full RRB Staff Nurse Kolkata-2015

Attempt every question from this paper in a timed mock, then review the full solution for each one.