Reasoning Blood Relations Rules

Blood-Relations – 60-Minute Revision Sheet for RRB

1. Golden Rule (Always Draw)

  • GENOGRAM: □ = Male, ○ = Female, ↔ = Couple, | = Parent–Child
  • ONE-LINE AGE RULE: Older generation ↑, Same generation →, Younger generation ↓
  • NEVER ASSUME GENDER FROM NAME – wait for clue.

2. Codewords → Instant Relations

Code Full Form Quick Note
M Mother Always female
F Father Always male
B Brother Male sibling
S Sister Female sibling
H Husband Male spouse
W Wife Female spouse
C Child Son/Daughter
P Parent M/F

Combine: MFS = Mother’s Father’s Son → Uncle.

3. Shortcut Formulas

Relation asked Formula in symbols Trick
Mother’s/Father’s only son Self “Only” → remove sibling
Son of my grandfather’s only son Self Work inside-out
Wife of my father’s father Grand-mother Two fathers cancel
Brother of my mother’s only child Self “only child” = me

4. Generation Ladder

  • +2 Great-grandparents
  • +1 Grand-parents / Uncle / Aunt
  • 0 Self, Siblings, Cousins
  • -1 Children
  • -2 Grand-children

5. Gender-Checker Tricks

  • Only son” → must be male.
  • Spouse of X” → opposite gender of X.
  • X is father of Y” → X male, Y can be any.
  • No info? → Keep both options (M/F) till last clue.

6. Mnemonics

  • FBS = “Father’s Brother Son” → Cousin brother.
  • MBD = “Mother’s Brother Daughter” → Cousin sister.
  • “FUCHSIA” – F-Father, U-Uncle, C-Cousin, H-Husband … list top relations quickly.

7. 30-Sec Elimination Plan

  1. Read Q twice → note gender & generation.
  2. Draw 3-generation tree (max).
  3. Put fixed clues first; leave blanks for unknown.
  4. Answer always in English word, NOT code.
  5. No negative marking? Attempt even if 50 % sure.

8. Table of Common Twists

Statement Hidden meaning
“Her mother is my mother’s only daughter” Speaker is the girl’s mother
“The man is the son of my wife’s husband” My son
“The lady is the daughter of my mother’s husband” Sister (step-sister included)

9. Rapid-Fire Q&A

Q1: Pointing to a man, Rita said, “His only brother is the father of my daughter.” How is Rita related to that man?Rita is the **wife** of the man (man’s only brother = Rita’s husband).
Q2: X introduces Y: “His mother’s brother is the father of my son.” How is Y related to X?Y is **nephew** of X (X is Y’s maternal uncle).
Q3: A is B’s sister. C is B’s mother. D is C’s father. E is D’s mother. What is A to D?A is **grand-daughter** of D.

10. Last-Day Quick Facts

  • Paternal = Father’s side; Maternal = Mother’s side.
  • Cousins are always same generation.
  • In-laws appear only after marriage in tree.
  • Double cousins = Father’s sibling + Mother’s sibling children (rarely asked).
  • No relation = mark “None of these” boldly.

11. One-Minute Recall Card

  1. Draw → 2. Code → 3. Generation → 4. Gender → 5. Answer.
    Done! Attempt, Revise, Repeat.