Blood Relations — SSC CHSL Study Notes
Overview
These problems test your ability to decode family relationships from verbal descriptions and either identify a specific relation or trace a connection between two persons.
Exam questions take three main forms: direct relationship identification (A is B's father; what is B to A?), coded/pointing problems (pointing to a photograph, a person says "Her mother is the only daughter of my mother"), and family-tree puzzles (multiple statements building a multi-generational tree). Mastery requires clarity on gender-specific terms (niece vs. nephew, maternal vs. paternal), generational direction (ascendant vs. descendant), and systematic diagram-drawing. Most errors come from misreading "only daughter" logic or confusing in-law versus blood relations. With practice, this is a high-accuracy topic where you can score full marks in under a minute per question.
Key Concepts
- Generation levels: Parents/uncles/aunts are one generation up (+1), siblings/cousins are same generation (0), children/nieces/nephews are one down (–1), and grandparents/grandchildren are ±2 respectively. Track vertical movement to avoid mixing generations.
- Gender markers: Always assign M (male) or F (female) when drawing trees. Terms like son, father, brother, husband, uncle, nephew are male; daughter, mother, sister, wife, aunt, niece are female. "Sibling" or "child" can be either gender.
- "Only" keyword traps: "Only son" means exactly one son (no brothers, but sisters may exist unless stated "only child"). "Only daughter of my mother" means the speaker herself if female, creating a self-reference chain often tested in coded problems.
- In-law relationships: Spouse's relatives or sibling's spouses. Mother-in-law is your spouse's mother or your child's spouse's mother. Brother-in-law can be your sister's husband, your spouse's brother, or your spouse's sister's husband — context determines which.
- Maternal vs. paternal: Maternal uncle (mama) is mother's brother; paternal uncle (chacha/tau) is father's brother. Maternal aunt (mausi) is mother's sister; paternal aunt (bua) is father's sister. Grandparents follow the same split.
- Symmetric relations: If A is B's uncle, B is A's nephew/niece. If A is B's cousin, B is also A's cousin. Use symmetry to reverse-check your answer.
- Diagramming discipline: Use + for male, ○ for female, = for marriage/horizontal sibling line, and | for parent-child vertical line. Write names inside symbols. Horizontal = same generation; vertical = parent/child link. Always start from a reference person and expand outward.
- Coded statements method: Replace pronouns with actual names, identify the reference person (usually "my"), then trace step-by-step. Example: "His mother" → go to the speaker's father's wife if "his" refers to speaker's brother.
Key Facts
- Brother's wife = sister-in-law (bhabhi). Sister's husband = brother-in-law (jija).
- Father's brother = paternal uncle. Father's sister = paternal aunt. Mother's brother = maternal uncle. Mother's sister = maternal aunt.
- Cousin = uncle's or aunt's child, same generation as you.
- Nephew = brother's or sister's son (male, –1 generation). Niece = brother's or sister's daughter (female, –1 generation).
- Grandson/Granddaughter = son's or daughter's child (–2 generation).
- Father-in-law = spouse's father. Mother-in-law = spouse's mother.
- Son-in-law = daughter's husband. Daughter-in-law = son's wife.
- Only child = no siblings at all. Only son = no brothers, may have sisters.
Worked Examples
Example 1 (Direct relationship) Statement: Pointing to a man, Priya said, "His brother's father is the only son of my grandfather." Question: How is the man related to Priya?
Solution:
- "Only son of my grandfather" = my father (since Priya's father is the single son).
- "His brother's father" = the man's father = my father.
- So the man's father = Priya's father → the man is Priya's brother. Answer: Brother.
Example 2 (Family-tree puzzle) Statements:
- A is the father of B and C.
- D is the wife of A.
- E is the brother of B.
- F is the daughter of D.
Question: How is F related to E?
Solution: Draw the tree:
- A (M) married to D (F). Children of A and D: B, C, E, F.
- Statement 3 says E is brother of B → E is male, same generation as B.
- Statement 4 says F is daughter of D → F is female child of D (and A).
- All four (B, C, E, F) are siblings.
- E is male, F is female, same generation → F is E's sister. Answer: Sister.
Example 3 (Coded "only daughter" trap) Statement: Looking at a portrait, a woman says, "Her mother is the wife of my father but she is not my sister." Question: Who is in the portrait?
Solution:
- "Wife of my father" = my mother.
- "Her mother" = portrait person's mother = my mother.
- So portrait person is my mother's child.
- She is not my sister → the only remaining option is the speaker herself (if female) or the speaker's daughter.
- Since "she is not my sister" rules out sibling, the portrait must be of the speaker's daughter. Answer: Daughter.
Example 4 (Generation counting) Statement: Rina is the granddaughter of Mohan, who is the father of Pradeep. Pradeep is the father of Arjun. Question: How is Rina related to Arjun?
Solution: Tree:
- Mohan → Pradeep → Arjun (three generations down: grandfather–father–son).
- Rina is granddaughter of Mohan → Rina is Pradeep's daughter.
- Pradeep's children: Rina (F), Arjun (M).
- Rina and Arjun are siblings (brother-sister). Answer: Sister (Rina is Arjun's sister).
Common Mistakes
- "Only daughter" confusion → Students assume "only daughter of my mother" means a separate person. Fix: If the speaker is female and her mother has only one daughter, the speaker herself is that daughter. Always check if self-reference applies.
- Mixing in-law with blood → Calling spouse's brother "brother" instead of "brother-in-law." Fix: Blood relation = direct lineage or sibling. In-law = through marriage. Keep them distinct.
- Ignoring gender in answers → Writing "sibling" when the question demands "brother" or "sister." Fix: Read the question carefully; if gender is specified or the answer options split by gender, commit to male or female.
- Backward generation movement → Confusing "son of my father" (which could be me or my brother) with "father of my son" (which is always me if male). Fix: Trace direction: "of my X" goes from me → X, then the next relation goes from X outward.
- Overcounting "only" → Assuming "only son" means "only child." Fix: "Only son" = no other sons (sisters can exist). "Only child" = no siblings at all. The word "child" must appear for the stronger condition.
Quick Reference
- Uncle's/Aunt's child = Cousin (same generation).
- Brother's/Sister's child = Nephew (M) or Niece (F) (one generation down).
- "Only son of my grandfather" = my father (if he's the sole son).
- "Her mother is my mother" → She is my sister or I am she (if both female).
- In-laws: Add "-in-law" for spouse's family or child's spouse.
- Always draw a quick tree for multi-step or puzzle problems — visual clarity prevents 90 % of errors.