CAT 2026 DILR Blood Relations and Family Tree Sets: A Notation System and 3 Solved Sets
A compact notation (gender markers, marriage equals-sign, parent arrow, ambiguity marker) plus a four-step tree-building method. Works three solved sets — a three-generation line, a branch with in-laws, and a gender-ambiguous set.
CAT 2026 DILR Blood Relations and Family Tree Sets: A Notation System and 3 Solved Sets
Blood relation sets are short to state and easy to misread. A single line of relationships, one careless assumption about who is male or whose child is whose, and the answer quietly flips. The logic is never the hard part. The hard part is reading the statements without adding facts the clues never gave you. A small diagram fixes that, because it forces you to record only what is stated. This guide gives you a universal notation system for blood relations and family tree sets in CAT 2026, a four-step way to build the tree, and three solved sets, including a gender-ambiguous one.
Why Blood Relation Sets Reward Notation
A blood relation set hands you a chain of relationships and asks how two people connect. The statements are compact, which makes them feel solvable in your head, and that is the trap. Hold three or four links mentally and you start filling gaps with assumptions, usually about gender or which generation someone belongs to.
A diagram removes the temptation. When every clue becomes a mark on a tree, you record exactly what was said and nothing more. The relationship the question asks for is then a path you trace through the tree, not a fact you reconstruct from memory. The set stops being about recall and becomes about careful reading.
A Universal Notation System
Three symbols cover almost every CAT blood relation set. Keep them consistent across every set you practise so the notation becomes second nature.
| Symbol | Meaning | Example |
|---|---|---|
| M or F after a name | Gender, when stated | A(M) is male |
| An equals sign between names | A married couple | A = B are married |
| A downward arrow | Parent to child | A → C means A is C's parent |
| Same level under a parent | Siblings | C and D under B are siblings |
| A question mark | Gender not yet known | B(?) is unfixed |
The question mark matters as much as the rest. Words like parent, child, sibling and spouse carry no gender, so the person stays marked with a question mark until a gendered word like father, sister or wife appears. That single habit prevents the most common error in the format.
The Four-Step Tree-Building Method
The method turns a line of statements into a tree you can read. Run these four steps on any blood relation set.
- List the people. Write each name once, adding M, F or a question mark for gender exactly as the clues state.
- Place couples and parents. Join married pairs with an equals sign, then drop arrows from parents to children to fix generations.
- Level the siblings. Put children of the same parents on one line so the generations stay clean.
- Trace the asked path. Walk from one person to the other through the tree and name the relationship you cross.
Building top to bottom keeps generations honest. Once couples and parent links are in, the tree usually answers more than the single question asked, so you can handle follow-ups without redrawing. The trace in step four is mechanical when the tree is clean.
Make Family Trees a Quick Win
Optima Learn drills blood relation sets with a fixed notation, so the short sets others misread become fast, certain marks for you.
Practise Family Tree Sets3 Solved Blood Relation Sets
Here are three sets that climb in difficulty: a three-generation line, a branch with in-laws, and a gender-ambiguous set. Read the reasoning, then redo each one cold.
R is the mother of S. S is the father of T. T is the daughter of S. How is R related to T?
R is female and the parent of S. S is male and the parent of T, who is female. Build the line top to bottom.
R is the parent of T's father, so R is the grandmother of T, specifically the paternal grandmother.
M is the wife of N. N is the son of O. O has only two children, N and P. P is the mother of Q. How is M related to Q?
N is male and a child of O, married to M. O's other child is P, who is female and the mother of Q. So P and N are siblings, which makes N the brother of Q's mother.
N is Q's maternal uncle, so M, as N's wife, is Q's aunt by marriage.
A is the father of B. B has two children, C and D. C is the sister of D. E is married to B. How is E related to A, and can D's gender be determined?
A is male and the parent of B. B has children C and D, and C is female. E is married to B. No clue states whether B is a son or a daughter, so B's gender stays a question mark, and E's gender does too.
E is married to A's child, so E is A's child-in-law, either a daughter-in-law or a son-in-law. The exact term needs B's gender, which is not given. D's gender is also undetermined, since C being a sister fixes only C as female.
Common Traps in Family Tree Sets
Most lost marks come from a few repeatable slips. Watch for these as you build the tree.
- Assuming a gender. Parent, child and spouse say nothing about gender. Leave a question mark until a gendered word appears.
- Collapsing a generation. A grandparent is two arrows away, not one. Keep each parent link as its own level.
- Forcing a determinate answer. If the asked relationship needs a gender the clues never fixed, the answer is cannot be determined.
Words like father, mother, son, daughter, brother, sister, husband and wife each lock a gender, so mark it the moment one appears. Words like parent, child, sibling and spouse do not, so they stay ambiguous. Treating gendered words as the only source of gender, and refusing to infer it from anything else, keeps your tree honest and your answers safe from the format's favourite trap.
Some sets are built so the precise term depends on a gender the clues never give. The general relationship still holds, a child-in-law or a sibling, but the specific one, daughter-in-law or brother, does not. Resist the urge to pick the more common option. Read the answer choices for a cannot-be-determined line, because that is usually the intended answer when a gender is left open.
Blood relation sets sit beside the other logical reasoning families, so practise them next to our guides on DILR logical reasoning puzzles and DILR binary logic sets. Build family tree practice into your wider CAT preparation, and review your set-selection accuracy each week with the CAT preparation tracker.
The reward is a quick, certain scorer. A blood relation set you can diagram in under a minute becomes a confident pick during selection, the kind that banks marks while others second-guess a generation. Keep this notation central to your CAT 2026 preparation and rehearse it until drawing the tree is the first thing you do.
Blood Relation Questions, Answered
Build DILR Accuracy You Can Trust
A personalised CAT 2026 plan that drills every DILR set type, tracks your accuracy by family, and builds the set-selection instinct that protects your score.
Strengthen My DILR
Solve real CAT DILR sets timed
Hand-picked LR puzzles and DI caselets with timer + solution breakdown.