Blood Relation Questions: 6 Patterns, 10 Worked Examples

Blood relation questions appear in every major campus placement test and consistently cost marks for students who skip the family tree step.

Where blood relation questions appear

TCS NQT, Infosys SP, Wipro National Talent Hunt, Cognizant GenC, Accenture cognitive ability, and Capgemini GamedIn all include blood relation questions in their logical reasoning or verbal ability sections. The Infosys campus placement process covers reasoning ability as a standalone section; blood relations is one of its five topic types alongside syllogisms, coding-decoding, statement-conclusion, and data sufficiency.

The skill being tested is not family-terminology memorisation. It is logical deduction: given a set of stated relationships, derive an unstated one by building a consistent relational chain. That distinction shapes how you should prepare. See the aptitude test preparation guide for the broader placement reasoning roadmap.

The 6 question patterns

Every blood relation question in a campus test fits one of six patterns. Recognising the pattern in the first few seconds determines how you set up the tree.

Pattern 1: Direct chain

A sequence of two or more stated relationships leads to one unstated relationship. Statements are plain prose with no coding. These are the most common type.

Pattern 2: Coded relations

Each relationship is replaced by a symbol or operator. A decoding key is provided. You decode each expression and then build the tree from the decoded statements.

Pattern 3: Paragraph puzzle

A paragraph describes a family with three or more members across multiple relationships. The question asks for one specific relationship inside that family.

Pattern 4: Generation arithmetic

The chain spans three or more generations. The question asks for a generation label: grandparent, great-grandparent, or further.

Pattern 5: Dialogue form

A character speaks using first-person pronouns (“my father,” “my mother’s brother”). The speaker is part of the relational chain and serves as the anchor node.

Pattern 6: Pointing puzzle

Someone points to a photograph or another person and states a relationship, for example “Her father is the only son of my grandfather.” The speaker is always the anchor of the chain.

Blood relation questions share a structural similarity with other logical reasoning types. Cryptarithmetic puzzles, for instance, require the same step-by-step constraint satisfaction, though with numeric rather than family chains.

The family-tree method

Three steps handle most blood relation questions:

• Step 1: Draw one box per named person in the problem. Write M or F beside each name if gender is stated or implied. Leave the box unmarked if gender is unknown.
• Step 2: Draw a downward arrow from parent to child for each stated parent-child link. Mark married couples with a horizontal line connecting their boxes.
• Step 3: Read the relationship between the two people the question asks about by tracing the path in the completed tree.

Two rules prevent most errors:

• Never assume gender. If the problem says “sibling” or “child” without specifying, keep the box unmarked until a later statement confirms it.
• In dialogue and pointing-puzzle patterns, the first node in your tree is always the speaker. Anchor every subsequent relationship to that starting node, not to the person being described.

10 worked examples

Direct chain

• Q1: A is the mother of B. B is the brother of C. How is A related to C?

  • Step 1: A is B’s mother, placing A one generation above B.
  • Step 2: B is C’s brother, so B and C are siblings sharing the same mother.
  • Step 3: A is B’s mother and B and C are siblings, so A is also C’s mother.
  • Answer: A is the mother of C.

• Q2: X is the son of Y. Y is the sister of Z. Z is the father of W. How is X related to W?

  • Step 1: X’s parent is Y (Y is X’s mother).
  • Step 2: Y is Z’s sister, so Y and Z are siblings with the same parents.
  • Step 3: Z is W’s father, placing Z one generation above W.
  • Step 4: Y is W’s aunt (the sister of W’s father Z). X is Y’s son, making X Z’s nephew by extension.
  • Step 5: X is the child of Z’s sister; W is Z’s child. Children of siblings are cousins.
  • Answer: X is the cousin of W.

Coded relations

• Q3: Key: P - Q means P is the mother of Q; P x Q means P is the father of Q; P + Q means P is the sister of Q. Expression: M - N x R + S. How is M related to S?

  • Step 1: M - N decodes as M is the mother of N.
  • Step 2: N x R decodes as N is the father of R.
  • Step 3: R + S decodes as R is the sister of S, which also means N is S’s father.
  • Step 4: M is N’s mother; N is the father of both R and S. M is therefore the grandmother of R and S.
  • Answer: M is the grandmother of S.

• Q4: Key: A # B means A is the husband of B; A @ B means A is the daughter of B. Expression: P @ Q # R. How is P related to R?

  • Step 1: P @ Q decodes as P is the daughter of Q.
  • Step 2: Q # R decodes as Q is the husband of R. Q (male) and R (female) are married.
  • Step 3: P is the daughter of Q; Q is R’s husband. P is therefore also the daughter of R.
  • Answer: P is the daughter of R.

Paragraph puzzle

• Q5: In a family, A and B are a married couple. C and D are A’s children. E is D’s husband. F is C’s daughter. How is F related to B?

  • Step 1: A and B are married, so they are the parents of C and D.
  • Step 2: C is A and B’s child. F is C’s daughter.
  • Step 3: F is A and B’s grandchild. B is therefore F’s grandparent.
  • Answer: F is the granddaughter of B.

• Q6: P is Q’s mother. Q is R’s brother. S is P’s mother-in-law. How is R related to S?

  • Step 1: P is Q’s mother. Q is R’s brother, so Q and R are siblings and P is also R’s mother.
  • Step 2: S is P’s mother-in-law, meaning S is the mother of P’s husband.
  • Step 3: P’s husband is the father of Q and R. S is the mother of R’s father.
  • Step 4: The mother of your parent is your grandparent.
  • Answer: R is the grandchild of S.

Generation arithmetic

• Q7: D is the mother of C. C is the mother of A. A is the grandmother of B. How is D related to B?
  • Step 1: Map the chain: D is one link above C; C is one link above A; A is two links above B (grandmother = 2 links).
  • Step 2: Total parent-child links from D down to B: 1 (D to C) + 1 (C to A) + 2 (A to B’s parent, then to B) = 4 links.
  • Step 3: Four parent-child links above a person = great-great-grandparent.
  • Answer: D is the great-great-grandmother of B.

Dialogue form

• Q8: A man says, “Her father is the only son of my grandfather.” How is the woman related to the man?
  • Step 1: Anchor the tree at the man (speaker).
  • Step 2: “My grandfather’s only son” is the man’s father, since the grandfather has exactly one son.
  • Step 3: The woman’s father equals the man’s father. They share the same father.
  • Step 4: Sharing the same father means they are siblings.
  • Answer: The woman is the man’s sister.

Pointing puzzle

• Q9: Pointing to a photograph, Anita says, “He is the son of my father’s only brother.” How is the person in the photograph related to Anita?

  • Step 1: Anchor at Anita (speaker).
  • Step 2: Anita’s father’s only brother is Anita’s uncle.
  • Step 3: The photographed person is Anita’s uncle’s son.
  • Answer: The person is Anita’s cousin.

• Q10: A woman says, “This boy’s mother is the daughter-in-law of my mother.” How is the boy related to the woman?

  • Step 1: Anchor at the woman (speaker).
  • Step 2: The woman’s mother’s daughter-in-law is the wife of the woman’s mother’s son, which is the wife of the woman’s brother.
  • Step 3: The boy’s mother is the woman’s brother’s wife, so the boy is the son of the woman’s brother.
  • Step 4: A person’s brother’s son is their nephew.
  • Answer: The boy is the woman’s nephew.

Four traps that cost marks

Trap 1: Assuming gender without a clue

If a problem says “sibling” or “child” without specifying gender, do not mark the box M or F. Forcing a gender early creates a wrong family tree. Hold the label open until a later statement in the problem confirms it.

Trap 2: Losing track of the narrator

In dialogue and pointing-puzzle variants, the speaker is always Node 1. Every described relationship is relative to that anchor. Students who start the tree from the described person rather than the speaker end up with an inverted family and a wrong answer.

Trap 3: Confusing in-laws with blood relatives

“Daughter-in-law of my mother” and “daughter of my mother” lead through different chains. In-law links pass through a marriage event. Trace to the married person first, then cross the marriage link to reach their family of origin.

Trap 4: Treating cousin as sibling

Siblings share both parents (same generation, one node apart). Cousins are the children of a parent’s sibling (same generation, two nodes removed). If two people share the same grandparent but have different parents, they are cousins, not siblings.

The step-by-step chain-building in the coded-relation and pointing-puzzle examples above (decode each statement, anchor at a fixed node, trace the path) is the same structured decomposition that makes prompt engineering click. TinkerLLM lets you apply that reasoning discipline to live LLM interactions at ₹299, no prior AI background needed.