Building a family tree from a chain of relationship statements — the most diagram-dependent topic in the entire reasoning section.
📖 ~13 min read🧩 SSC Reasoning
Introduction
Blood Relations questions describe a chain of family connections in words, and ask you to determine how
two people are related — the single most effective technique is drawing a quick family tree
diagram as you read each clue, rather than trying to hold it all in your head.
Diagram — Sample Family Tree
E is A and B's grandson, D's nephew, and C's son — all read directly off the tree instead of re-deriving each relationship from the text.
Basic Relationship Terms
Relation
Meaning
Sibling
Brother/sister (same parents)
Maternal
Related through the mother's side (e.g., maternal uncle = mother's brother)
Paternal
Related through the father's side
Nephew/Niece
Sibling's son/daughter
Cousin
Child of one's uncle/aunt
In-laws
Related by marriage (e.g., father-in-law = spouse's father)
Symbol-Based Blood Relations (Coded)
Some questions use symbols (e.g., "A + B" means A is mother of B, "A × B" means A is brother of B) — the strategy is identical: draw the tree using the symbol key as you go.
Q. If "P + Q" means P is the mother of Q, and "Q × R" means Q is the brother of R, what is the relation of P to R?
P is mother of Q; Q is brother of R → so Q and R are siblings, sharing the same mother, P
P is the mother of R
Classic Word-Problem Pattern
Q. Pointing to a photograph, a man says, "She is the daughter of my grandfather's only son." How is the girl related to the man?
"My grandfather's only son" = the man's father (since the man himself is also a son of the grandfather, but "only son" implies the father is the sole son — meaning the man IS that son, or it's the man himself)
If "my grandfather's only son" = the man's father, then the daughter of the man's father = the man's sister
Q. A is B's brother. B is C's sister. C is D's father. How is A related to D?
A and B are siblings; B is C's sister → B and C are siblings too → A, B, C are all siblings
C is D's father → A is C's brother → A is D's uncle
💡 Exam Tip: Always draw the tree with a consistent symbol system — e.g., a straight line for "married to," and a downward branch for "parent of" — and mark gender (M/F) wherever stated. Most errors in this chapter come from skipping the diagram and trying to track relations mentally.
✅ Practice Focus: Building a family tree diagram clue-by-clue · Maternal vs paternal side distinction · Symbol-coded blood relation decoding · "Pointing to a photograph" classic word-problem pattern.