Blood Relations – Simple Study Notes
(For Bihar PSC – Reasoning Ability)
1. What are Blood Relations?
Blood relations are people who share the same family tree.
Think of it as a family web where every link is a parent‑child connection.
- Direct line – parent → child (father, mother, son, daughter).
- Sideways – siblings (brother, sister).
- Cross‑branch – cousins (children of your aunts or uncles).
2. Everyday Names for Blood Relatives
| Relation | How we call them in everyday life | How it looks on the family tree |
|---|---|---|
| Father | Dad | Parent → Child |
| Mother | Mom | Parent → Child |
| Son | My son | Child → Parent |
| Daughter | My daughter | Child → Parent |
| Brother | My brother | Same parent, same generation |
| Sister | My sister | Same parent, same generation |
| Uncle | Uncle (father’s brother or mother’s brother) | Parent’s sibling |
| Aunt | Aunt (father’s sister or mother’s sister) | Parent’s sibling |
| Cousin | Cousin (child of an uncle/aunt) | Child of a parent’s sibling |
3. Rules That Always Hold
-
Parent ↔ Child – opposite of each other.
If X is Y’s father, Y is X’s son. -
Sibling – share both parents.
If two people are siblings, they are each other’s brother/sister. -
Uncle/Aunt and Niece/Nephew – opposite of each other.
If X is Y’s uncle, Y is X’s niece/nephew. -
Cousin – children of siblings.
If X’s father is Y’s uncle, X and Y are cousins. -
Marriage does not change blood relations – only “in‑law” relations.
4. How to Read a Blood‑Relation Question
- Write down the given facts – each fact is a link in the tree.
- Start from the known person – usually the one mentioned first.
- Move step by step – go up to a parent or down to a child, or sideways to a sibling.
- Keep track of generation levels – use “–1” for parent, “+1” for child.
- Ask the final question – who is the person you need?
Analogy: Imagine you are on a ladder.
- Going up one rung = parent.
- Going down one rung = child.
- Moving left/right on the same rung = sibling.
5. Tiny Example
Facts
- Ravi is the son of Meena.
- Meena is the daughter of Sita.
- Sita is the sister of Raj.
Question – Who is Ravi’s uncle?
Step‑by‑step
| Step | Move | Person | Reason |
|---|---|---|---|
| 1 | Down | Ravi | Start from Ravi |
| 2 | Up | Meena | Ravi’s mother |
| 3 | Up | Sita | Meena’s mother |
| 4 | Sideways | Raj | Sita’s brother |
| 5 | Down | Ravi | Back to Ravi |
Answer: Ravi’s uncle is Raj.
6. Quick Practice Problems
| # | Question | Answer |
|---|---|---|
| 1 | If A is the brother of B, and B is the son of C, who is A to C? | A is C’s son (A is also the son of C). |
| 2 | J is the daughter of K. K is the brother of L. Who is J to L? | J is L’s niece. |
| 3 | M is the mother of N. N is the sister of O. Who is O to M? | O is M’s son. |
| 4 | P is the father of Q. Q is the daughter of R. Who is R to P? | R is P’s wife (not a blood relation). |
| 5 | S is the cousin of T. T is the daughter of U. Who is S to U? | S is U’s nephew/niece. |
7. Tips for the Exam
- Draw a quick sketch of the tree if the question is long.
- Use abbreviations that you are comfortable with:
P= Parent,C= Child,S= Sibling,U= Uncle/Aunt,N= Niece/Nephew,Cu= Cousin.
- Check for double negatives – e.g., “not a brother” means “not a sibling.”
- Remember the order – parent → child → sibling → parent’s sibling → cousin.
Final Thought
Blood relations are just a family map.
Treat each fact as a street sign, and follow the map step by step to reach the destination.
Good luck with your Bihar PSC preparation!