⭐ Sabse Important Points · एक नज़र में
- Generation Gap: Count the number of generations between two individuals to determine if they are of the same generation (siblings, cousins) or different (parent-child, grandparent-grandchild).
- Symbol Decoding: Create a quick key for each symbol (e.g., '+' = father, '-' = mother, '×' = brother, '÷' = sister) before solving.
- Gender Indicators: Words like 'his', 'her', 'son', 'daughter' indicate gender; use them to avoid confusion.
- Chain Rule: For expressions like 'A + B × C', interpret as A is father of B, B is brother of C, so A is father of C (if C is male/female accordingly).
- Self-Reference: If the question says 'pointing to a photograph, a man said, "She is the daughter of my grandfather's only son"', identify 'my grandfather's only son' as the man's father, so the girl is his sister.
- Elimination Technique: In puzzles, eliminate impossible relationships based on gender and generation clues.
Introduction · परिचय
Blood Relations is a key reasoning topic in the Delhi Police Constable exam. It tests your ability to decode family relationships from given statements, puzzles, or symbolic representations. Mastery requires understanding kinship terms, drawing family trees, and applying logical deductions.
Basic Blood Relations and Family Tree
Blood relations involve identifying how two people are related based on given information. A family tree is a diagram that shows relationships across generations. Key terms include: father, mother, brother, sister, son, daughter, grandfather, grandmother, uncle, aunt, cousin, nephew, niece, etc. Always use standard symbols: square for male, circle for female, horizontal line for marriage, vertical line for offspring.
- Identify the reference person
- Break down each relation step by step
- Assign gender and generation
- Connect with family tree symbols
- Determine final relationship
⭐ Key Points · याद रखने वाली बातें
- Generation Gap: Count the number of generations between two individuals to determine if they are of the same generation (siblings, cousins) or different (parent-child, grandparent-grandchild).
- Gender Indicators: Words like 'his', 'her', 'son', 'daughter' indicate gender; use them to avoid confusion.
- Self-Reference: If the question says 'pointing to a photograph, a man said, "She is the daughter of my grandfather's only son"', identify 'my grandfather's only son' as the man's father, so the girl is his sister.
✍️ Solved Example 1 · हल किया हुआ उदाहरण
❓ Question: Pointing to a photograph, a woman says, 'He is the son of my mother's only son.' How is the man related to the woman?
✅ Solution: Nephew
💡 Explanation: The woman's mother's only son is her brother. The son of her brother is her nephew. So the man is her nephew.
Coded Blood Relations and Puzzle-Based Relations
In coded blood relations, relationships are represented by symbols or codes (e.g., A + B means A is father of B). You must decode the symbols and then solve. Puzzle-based relations give a set of statements and ask for the relationship between two specific individuals. Approach: decode each statement, draw a combined family tree, and answer.
📐 Formula / Rule Box · सूत्र याद रखो
Common Symbols
+ : Father, - : Mother, × : Brother, ÷ : Sister
Chain Rule
For expressions like 'A + B × C', interpret as A is father of B, B is brother of C, so A is father of C (if C is male/female accordingly).
| Direct Relation | Coded Relation |
|---|---|
| Stated in words | Stated using symbols |
| Easier to interpret | Requires decoding first |
| Example: 'A is father of B' | Example: 'A + B' |
⭐ Key Points · याद रखने वाली बातें
- Symbol Decoding: Create a quick key for each symbol (e.g., '+' = father, '-' = mother, '×' = brother, '÷' = sister) before solving.
- Elimination Technique: In puzzles, eliminate impossible relationships based on gender and generation clues.
✍️ Solved Example 1 · हल किया हुआ उदाहरण
❓ Question: If 'P + Q' means P is the father of Q, 'P - Q' means P is the mother of Q, and 'P × Q' means P is the brother of Q, then in 'A + B - C', how is A related to C?
✅ Solution: Grandfather
💡 Explanation: A + B means A is father of B. B - C means B is mother of C. So A is the father of C's mother, i.e., maternal grandfather.
Practice Questions · खुद हल करके देखो
पहले खुद try karo, phir “Answer dekho” dabakar check karo. 👇
Q1A is B's sister. C is B's mother. D is C's father. E is D's mother. How is A related to D?
👀 Answer dekho
✅ Answer: Granddaughter
💡 Explanation: A is sister of B, so A is child of C. C is daughter of D (since D is C's father). Therefore, A is granddaughter of D.
Q2If 'X $ Y' means X is the wife of Y, 'X # Y' means X is the son of Y, and 'X * Y' means X is the daughter of Y, then in 'P $ Q # R', how is P related to R?
👀 Answer dekho
✅ Answer: Daughter-in-law
💡 Explanation: P $ Q means P is wife of Q. Q # R means Q is son of R. So P is the wife of R's son, i.e., daughter-in-law of R.
Q3Pointing to a man, a woman said, 'His mother is the only daughter of my mother.' How is the woman related to the man?
👀 Answer dekho
✅ Answer: Mother
💡 Explanation: The only daughter of the woman's mother is the woman herself. So the man's mother is the woman. Hence, the woman is the man's mother.
⚠️ Common Mistakes · ये गलतियाँ बिल्कुल मत करना
- Assuming gender from names: Do not assume 'Alex' is male or 'Sam' is female; rely only on given indicators.
- Ignoring 'only' in statements: 'Only son' or 'only daughter' provides critical information; missing it leads to wrong conclusions.
- Overlooking generation gaps: Always count generations to avoid mixing up uncle/nephew or grandfather/grandson.
⚡ Quick Revision · Exam से पहले 2 मिनट में दोहराओ
- Family Tree Symbols: Square for male, circle for female, horizontal line for marriage, vertical line for children.
- Coded Relations: Decode symbols first, then apply chain rule; common codes: + father, - mother, × brother, ÷ sister.
- Puzzle Approach: Draw a combined tree, mark genders and generations, then answer the specific relationship asked.