Blood Relations – Study Notes
(Uttar Pradesh Forest Guard – Reasoning Ability)
1. Simple Explanation
Blood relations are the kinship ties that arise from a common ancestor (i.e., they are not formed by marriage).
In reasoning tests, you’ll be asked to determine the relationship between two people, or to deduce a missing link in a family tree.
Key idea:
A person’s relation to another is always defined by the shortest chain of “parent‑child” steps that connects them.
2. Key Points
| Term | Common Abbreviation | What It Means | Example |
|---|---|---|---|
| Father | F | Parent of a son or daughter | A’s F = B |
| Mother | M | Parent of a son or daughter | A’s M = C |
| Brother | Br | Male sibling (same parents) | A’s Br = D |
| Sister | S | Female sibling | A’s S = E |
| Son | S | Male child | A’s S = G |
| Daughter | D | Female child | A’s D = H |
| Grand‑father / Grand‑mother | GF / GM | Parent of a parent | A’s GF = I |
| Grand‑son / Grand‑daughter | GS / GD | Child of a child | A’s GS = J |
| Uncle / Aunt | U / A | Sibling of a parent | A’s U = K |
| Cousin | C | Child of an uncle/aunt | A’s C = L |
| Niece / Nephew | Ne / Np | Child of a sibling | A’s Ne = M |
| Great‑grandparent / Great‑grandchild | GGF / GGD | Grand parent’s parent / child’s child | A’s GGF = N |
2.1 Rules for Determining Relationships
| Rule | What It Says | How to Use It |
|---|---|---|
| Transitivity | If X is parent of Y, and Y is parent of Z → X is grand‑parent of Z. | Chain parent → parent → … |
| Symmetry (Sibling) | If X is sibling of Y → Y is sibling of X. | Swap the order. |
| Direction Matters | Parent → child vs. child → parent. | Keep track of “up” and “down” steps. |
| Same Generation | If two people have the same number of steps up to a common ancestor, they are of the same generation (cousins, siblings). | Count upward steps. |
| “Down‑Down” vs. “Up‑Up” | Two people can be related by moving down the tree (descendants) or up the tree (ancestors). | Use a diagram to keep track. |
2.2 Common Question Types
- Direct Relation – “What is the relation of X to Y?”
- Indirect Relation – “If X is the brother of Y, and Y is the mother of Z, what is X to Z?”
- Chain Questions – “If A is the son of B, B is the brother of C, and C is the mother of D, who is A to D?”
- Missing Link – “Fill in the blank: X is the ____ of Y.”
- Multiple People – “In the following family, who is the sister of the person who married the son of B?”
3. Worked Example
Problem
Statement
- A is the son of B.
- B is the brother of C.
- C is the mother of D.
- D is married to E.
Question – What is the relationship between A and E?
Step‑by‑Step Solution
| Step | What We Know | Visual Representation | Relationship Result |
|---|---|---|---|
| 1 | A → son of B | A ← B |
B is A’s father |
| 2 | B → brother of C | B ↔ C |
C is B’s sister |
| 3 | C → mother of D | C ← D |
D is C’s son |
| 4 | D → married to E | D – E |
E is D’s wife |
Chain from A to E
- A’s father = B
- B’s sister = C (so C is A’s aunt)
- C’s son = D (so D is A’s cousin)
- D’s wife = E (so E is A’s cousin‑in‑law)
Answer: E is the cousin‑in‑law of A (commonly referred to as cousin’s wife).
Quick Diagram (ASCII)
B (father of A)
|
A
|
C (sister of B) → D (son of C) → E (wife of D)
4. Quick Revision Summary
- Identify the direction (up = ancestors, down = descendants).
- Count the steps to find the generational difference.
- Use symmetry for siblings.
- Keep a simple diagram – even a single line of arrows works.
- Remember common abbreviations – they