RRB Group D Reasoning Blood Relation (Part 2) By Deepak Sir

Blood Relation Introduction

Blood relations form a significant part of the reasoning sections in competitive exams. These questions test a candidate's ability to determine familial relationships based on given information, often presented in complex or coded forms. Mastering these concepts and strategic problem-solving approaches is crucial for accurately and efficiently tackling such questions in RRB Group D or other competitive exams.

Review of Basic Notation and Relationships

Solving blood relation problems effectively relies on a clear understanding of standard notation. This visual representation helps in constructing family trees and quickly identifying relationships.

• Male: Represented with a positive sign (+).

• Female: Represented with a negative sign (-).

• Siblings (संगे भाई-बहन): If A and B are siblings, their relationship is shown with a single bond and a double cap (A -- B).

• Married Couple: Represented with a double bond and a double cap (A == B).

• Offspring (संतान): The parent-child relationship is shown with a single bond and a single cap, with the parent in the generation above the child.

Coded Blood Relations With Example

In coded blood relation problems, symbols replace direct relationship terms. These problems typically require you to decode the expressions and work from right to left to build the family tree.

Question:

Given the expression: Alpha + Beta - Dollar + Copyright * Hash, how is Alpha related to Dollar?

• A * B means A is the sister of B.

• A + B means A is the brother of B.

• A - B means A is the mother of B.

Solution Steps:

1. Copyright * Hash: Copyright is the sister of Hash.

2. Dollar + Copyright: Dollar is the brother of Copyright. This implies Dollar, Copyright, and Hash are siblings.

3. Beta - Dollar: Beta is the mother of Dollar. Since Dollar and Copyright are siblings, Beta is their mother.

4. Alpha + Beta: Alpha is the brother of Beta.

Family Tree:

• Alpha (+) is the brother of Beta (-).

• Beta is the mother of Dollar (+), Copyright (-), and Hash (gender unknown).

Conclusion: Alpha is the brother of Dollar's mother. Therefore, Alpha is Dollar's maternal uncle.

Coded Blood Relations: Finding the Correct Equation

This problem type requires you to identify the equation that correctly represents a given relationship. A key shortcut involves confirming gender.

Question:

If M is the maternal uncle of T, which of the following equations is correct?

• A x B means A is the brother of B.

• A ÷ B means A is the sister of B.

• A - B means A is the mother of B.

Problem-Solving Shortcut: Gender Confirmation

1. First, confirm the required gender of the key person. M must be a maternal uncle, which means M must be male.

2. Analyze the operators associated with M in the given options.

• If any option defines M as a female (e.g., M ÷ X, where ÷ means sister), that option can be immediately eliminated.

3. With options reduced, check one of the remaining choices. If it's correct, that's the answer. If not, the other remaining valid option must be correct.

Checking Option (C): M x K - T

1. K - T: K is the mother of T.

2. M x K: M is the brother of K.

• This establishes M as male, which aligns with being a maternal uncle.

Conclusion:

The equation shows that M is the brother of T's mother. This makes M the maternal uncle of T. Therefore, option (C) is the correct answer.

Photograph-Based Questions

These "pointing" questions involve one person describing another's relationship, often seen as challenging due to complex phrasing.

Methods for Solving:

1. Family Tree: Drawing a diagram of relationships.

2. Self-Substitution: Mentally placing yourself as the speaker.

3. Language Cutting Method: Breaking down complex phrases into simpler parts. For instance, "My wife's son's father" simplifies to "my son's father," which is "myself."

Example 1: The Common Mistake

Question: Pointing to a photograph, a person says, "I have no brother or sister, but that man's father is my father's son." Whose photograph was it?

Analysis of the common error: Many mistakenly conclude the person is pointing to their own photo.

Correct Step-by-Step Solution:

1. The speaker states: "I have no brother or sister." This is crucial. It means the speaker is an only child.

2. Focus on the core statement: "…that man's father is my father's son."

3. Break down the second part: "my father's son". Since the speaker has no brother, his father's only son must be the speaker himself.

4. Substitute this back: "that man's father is myself."

5. This means the speaker is the father of the person in the photograph.

Conclusion: The photograph is of the speaker's son or daughter.

Additional Examples of Photograph-Based Questions

These examples further illustrate the application of the language cutting method.

Example 2

• Question: Introducing a person, a woman said, "His wife is my father's only daughter." How is the woman related to that person?

• Solution: "My father's only daughter" refers to the woman herself. The statement simplifies to "His wife is myself." Therefore, the woman is the person's wife.

Example 3

• Question: Introducing a girl, Anil said, "Her mother is my mother-in-law's only daughter." How is Anil related to the girl?

• Solution: "My mother-in-law's only daughter" refers to Anil's wife. The statement simplifies to "Her mother is my wife." If the girl's mother is Anil's wife, then Anil is the girl's father.

The Golden Rule of Blood Relations

You can never define a person's gender by their name in blood relation problems.

Names can be gender-neutral or common to both genders (e.g., Sonu, Neeraj). Gender must be explicitly stated (e.g., "he," "she") or logically deduced from relationships.

Illustrative Example:

• Question: Reena said to Meena, "Your father is my son-in-law." How is Reena related to Meena's mother?

• Analysis:

1. Meena's father is Reena's son-in-law.

2. This means Reena's child is married to Meena's father.

3. Therefore, Reena's child is Meena's mother.

4. The question asks for the relationship between Reena and Meena's mother. Reena is the parent of Meena's mother.

• The Trap: The name "Reena" often sounds female, leading to the assumption that Reena is the mother of Meena's mother (i.e., Meena's maternal grandmother).

• Correct Conclusion: Because we cannot assume gender from the name, Reena could be the mother or the father of Meena's mother. The relationship is either Mother or Father.

Final Worked Example (Apostrophe-based)

These questions involve possessive phrasing which needs careful breakdown.

Question: Pointing to a woman, Taran said, "She is the mother of the father-in-law of my husband." How is Taran related to that woman?

Solution Breakdown:

1. Start from the innermost part: "my husband".

2. Next: "the father-in-law of my husband". A husband's father-in-law is his wife's father. So, this refers to Taran's father.

3. Final statement: "She is the mother of [Taran's father]."

4. The mother of Taran's father is Taran's paternal grandmother.

5. The question asks how Taran is related to the woman. If the woman is Taran's grandmother, then Taran is her granddaughter.