General Aptitude: Blood Relation Shortcuts
Master the family tree method for blood relation questions in CSIR-NET, GATE, and CUET-PG with diagram rules, traps, and two solved practice questions.
This guide explains how to solve blood relation questions using the family tree method. You will learn diagram symbols, common exam traps, two worked practice questions, and a four-week study plan.
Core principles of the family tree method
Blood relation questions test logical deduction by describing connections through birth or marriage. Drawing a family tree converts wordy statements into a clear, verifiable diagram.
A standard family tree uses five visual conventions:
- Generation levels: Place generations vertically with grandparents at the top, parents in the middle, and children at the bottom.
- Gender indicators: Mark males with (+) and females with (-). If gender is unstated, leave the indicator blank.
- Marriage bonds: Connect spouses using a double horizontal line (=).
- Sibling bonds: Connect siblings using a single horizontal line (-).
- Parent-child links: Connect parents to children using a vertical downward line (|).
Paternal relatives connect through your father, such as a paternal uncle. Maternal relatives connect through your mother, such as a maternal uncle. Nieces are daughters of siblings, nephews are sons of siblings, and cousins have no implied gender.
| Relationship | Diagram notation | Generation gap |
|---|---|---|
| Parent to child | Vertical line downward (|) | +1 generation |
| Grandparent to grandchild | Two vertical steps downward | +2 generations |
| Husband and wife | Double horizontal line (=) | 0 (same generation) |
| Brother and sister | Single horizontal line (-) | 0 (same generation) |
| Child to parent | Vertical line upward (|) | -1 generation |
The exam angle: blood relations in graduate entrance papers
General aptitude is an essential component in graduate entrance tests like CSIR-NET, GATE, IIT-JAM, and CUET-PG. Questions test your ability to apply logical constraints quickly without making unverified assumptions.
Questions appear in two formats: coded relations and narrative puzzles. Coded relations substitute mathematical operators for kinship ties. Narrative puzzles describe family connections across multiple generations.
Watch out for three recurring traps:
- Assuming gender from names: Names do not establish gender in formal logic. If an individual has a personal name, do not assign a gender until the text explicitly uses terms like son, daughter, mother, father, brother, sister, husband, or wife.
- Inverting question direction: If your tree shows P is the father of Q, check who the prompt targets. If asked for the relation of Q to P, the answer is son or daughter, not father.
- Ambiguous kinship terms: Words like in-law have multiple meanings. A sister-in-law may be the wife of a brother, the sister of a husband, or the sister of a wife. Inspect the exact branch on your tree before answering.
Practice question 1: coded blood relations
Practice question (question bank item ga-br-101)
Read the symbolic definitions below:
- P + Q means P is the sister of Q.
- P - Q means P is the brother of Q.
- P × Q means P is the mother of Q.
- P ÷ Q means P is the father of Q.
Which expression indicates that M is the maternal grandmother of T?
- Option A: M × R + S × T
- Option B: M ÷ R - S × T
- Option C: M × R - S ÷ T
- Option D: R × M + S × T
Step-by-step solution:
For M to be the maternal grandmother of T, M must be female, two generations above T (+2 generation gap), and the mother of the mother of T.
Evaluate Option A: M × R + S × T.
Step 1: M × R shows M is the mother of R (female, +1 generation).
Step 2: R + S shows R is the sister of S. Because M is the mother of R, M is also the mother of S.
Step 3: S × T shows S is the mother of T (female, +1 generation above T).
Because S is the mother of T, and M is the mother of S, M is the maternal grandmother of T. Option A is correct.
Other choices fail: Option B makes M male. Option C makes S male. Option D misplaces M in the chain.
Practice question 2: multi-generation puzzle
Practice question (question bank item ga-br-102)
A family consists of six members: J, K, L, M, N, and P. Consider these clues:
- There are two married couples in the family.
- M is the grandmother of J and mother of K.
- L is the wife of K and mother of P.
- P is the granddaughter of N.
- N is male.
Answer the following two questions:
- How is N related to K?
- How is J related to P?
Step-by-step solution:
Construct the family tree across three generations:
Step 1: M is the mother of K. Place M in the first generation as female (-) and K in the second generation. Because M is the grandmother of J, J belongs to the third generation.
Step 2: L is the wife of K. Connect K (+) and L (-) with a double line in the second generation. L is the mother of P, placing P in the third generation.
Step 3: P is the granddaughter of N, and N is male (+). Because the parents of P are K and L, N must be a grandfather. Because M is the mother of K, N (+) and M (-) form the married couple in the first generation.
Step 4: Members J and P are children of K and L in the third generation. P is a granddaughter, so P is female (-). However, no clue reveals whether J is male or female.
Conclusions:
- Question 1: N is the father of K.
- Question 2: J is the sibling of P. Because the gender of J is unstated, the exact relation is brother or sister.
Four-week study plan for blood relation questions
A four-week routine builds speed and precision alongside chemical science study. Practice with a question bank by chapter to reinforce every pattern:
- Week 1: Notation and core relations. Translate kinship statements into tree diagrams. Master terms like maternal uncle, paternal aunt, nephew, niece, and in-laws. Draw diagrams for ten statements daily.
- Week 2: Narrative puzzles. Solve paragraphs describing families of five to eight members. Fix married couples first, then branch downward to offspring. Mark unconfirmed genders with a question mark.
- Week 3: Coded relations. Solve problems with operational codes. Check the gender of the subject and net generation gap to discard incorrect choices quickly.
- Week 4: Timed sets and error tracking. Solve sets of ten mixed questions within fifteen minutes. Log mistakes in a notebook and categorize errors into gender assumptions, inverted relations, or misread clues.
Key takeaways
- A family tree simplifies verbal kinship puzzles by organizing individuals into clear vertical generations.
- Never deduce gender from a personal name; rely solely on explicit relationship terms in the text.
- In coded relations, filter choices quickly by checking the gender of the subject and calculating net generation gaps.
- Verify question direction to confirm which person serves as the reference point.
Frequently asked questions
What is the generation gap method in coded relations?
The generation gap method assigns values to relationship codes: +1 for parents, 0 for siblings or spouses, and -1 for children. Summing these values eliminates options that fail to match the required generation level.
Can gender be assumed from an everyday name in aptitude questions?
Aptitude tests rely strictly on deductive logic. Unless the problem defines gender through terms like mother, father, brother, sister, husband, or wife, the gender remains undetermined.
What is the difference between paternal and maternal relatives?
Paternal relatives connect through your father (such as a paternal uncle). Maternal relatives connect through your mother (such as a maternal uncle).
How should in-laws be represented on a family tree?
Represent in-laws by linking a marriage connection to a sibling or parent branch. For example, to show the wife of a brother, draw your brother on your sibling line, then attach a double horizontal line to his wife.
