How to Solve Blood Relation Problems

How to Solve Blood Relation Problems

(For SSC, Bank, Railway Exams – Ace Your Reasoning Section!)

Introduction

"Blood relation problems can give you 3-5 easy marks in SSC, Bank, or Railway exams—if you decode the family tree in under 60 seconds. Miss this, and you’re leaving free points on the table!

What You Need To Know First

1. Basic family terms (father, mother, son, daughter, brother, sister).
2. Gender symbols (♂ = male, ♀ = female).
3. How to draw a family tree (use lines and arrows to show relationships).

Key Vocabulary

Formulas To Know

(No complex formulas—just MEMORIZE these relationships!)

1. Parent → Child
2. Father/Mother → Son/Daughter

3. Example: If A is B’s father, B is A’s child.

4. Sibling Relationship

5. Same parents = siblings.

6. Example: If X and Y have the same mother, they are siblings.

7. Spouse Relationship

8. Husband ↔ Wife (no blood relation).

9. Example: If P is Q’s husband, Q is P’s wife.

10. In-law Relationship

11. Mother-in-law = Spouse’s mother.
12. Father-in-law = Spouse’s father.
13. Brother-in-law = Spouse’s brother OR Sister’s husband.
14. Sister-in-law = Spouse’s sister OR Brother’s wife.

Step-by-Step Method

Follow these 6 steps for EVERY blood relation problem:

1. Read the question carefully. Underline key names and relationships.
2. Draw a family tree. Start with the oldest generation at the top.
3. Use symbols:
4. ♂ = Male, ♀ = Female
5. = = Married couple
6. | = Parent-child connection
7. — = Siblings
8. Fill in known relationships. Work from the given info.
9. Eliminate impossible options. Cross out answers that don’t fit.
10. Verify the answer. Check if it matches the question.

WORKED EXAMPLE (Using the Steps)

Question: "A is B’s sister. C is B’s mother. D is C’s father. How is D related to A?"

Step 1: Underline key info. - A = B’s sister - C = B’s mother - D = C’s father

Step 2: Draw the family tree.

D (♂)
|
C (♀)
/   \
A (♀)  B (?)

(Since A is B’s sister, B’s gender isn’t specified—we don’t need it!)

Step 3: Fill relationships. - D is C’s father → D is A’s grandfather (because C is A’s mother).

Step 4: Eliminate wrong options. - Not "father" (C is the mother). - Not "uncle" (D is not C’s brother). - Not "brother" (D is male, A is female).

Step 5: Verify. - D → C → A = Grandfather → Granddaughter.

Answer: D is A’s grandfather.

What we did and why: We built the family tree step-by-step to avoid confusion. The key was recognizing that D is two generations above A.

Worked Examples

Example 1 – Basic

Question: "P is Q’s son. R is Q’s husband. How is R related to P?"

Solution:
1. P = Q’s son → Q is P’s mother.
2. R = Q’s husband → R is P’s father.

Answer: R is P’s father.

What we did and why: We linked the relationships directly. No extra generations—just parent-child and spouse.

Example 2 – Medium

Question: "X and Y are siblings. Z is Y’s daughter. W is X’s son. How is Z related to W?"

Solution:
1. X and Y = siblings.
2. Z = Y’s daughter → Z is X’s niece.
3. W = X’s son → W is Z’s cousin (because Z is Y’s child, and Y is X’s sibling).

Answer: Z is W’s cousin.

What we did and why: We had to track two branches of the family (X and Y) and see how their children (Z and W) relate.

Example 3 – Exam-Style (Time-Pressure)

Question: "Pointing to a photo, Raj said, ‘She is the daughter of my grandfather’s only son.’ How is the girl in the photo related to Raj?"

Solution:
1. "My grandfather’s only son" = Raj’s father (since grandfather’s only son is Raj’s dad).
2. "Daughter of my father" = Raj’s sister.

Answer: The girl is Raj’s sister.

What we did and why: We broke the sentence into parts. "Only son" is crucial—it means no uncles/aunts, so the daughter must be Raj’s sister.

Common Mistakes

Exam Traps

1-Minute Recap (Night Before Exam)

"Listen up! Blood relation problems are all about drawing a family tree. Here’s the drill:
1. Underline names and relationships—don’t miss a word.
2. Start with the oldest person and work down.
3. Use symbols: ♂ for male, ♀ for female, = for marriage, | for parent-child.
4. If it says "only son," there are no other brothers—lock that in!
5. For photo questions, rewrite the sentence in simple terms (e.g., "grandfather’s only son" = your dad).
6. Double-check: Does your answer match the question? If not, re-draw the tree.

You’ve got this—3 marks are yours!