Blood relation problems revolve around understanding family connections. To solve them effectively, you need a clear grasp of familial terms and a systematic approach to visualizing relationships.

Key Terminology:

Before we begin, let’s clarify common terms:

• Parent: Father or Mother.
• Child: Son or Daughter.
• Sibling: Brother or Sister.
• Spouse: Husband or Wife.
• Grandparent: Father’s father/mother, or Mother’s father/mother.
  • Paternal Grandfather: Father’s father.
  • Paternal Grandmother: Father’s mother.
  • Maternal Grandfather: Mother’s father.
  • Maternal Grandmother: Mother’s mother.
• Grandchild: Son’s son/daughter, or Daughter’s son/daughter.
  • Grandson: Son’s son or Daughter’s son.
  • Granddaughter: Son’s daughter or Daughter’s daughter.
• Uncle/Aunt:
  • Paternal Uncle: Father’s brother.
  • Maternal Uncle: Mother’s brother.
  • Paternal Aunt: Father’s sister.
  • Maternal Aunt: Mother’s sister.
• Niece/Nephew:
  • Niece: Brother’s daughter, Sister’s daughter, or Spouse’s sibling’s daughter.
  • Nephew: Brother’s son, Sister’s son, or Spouse’s sibling’s son.
• Cousin: Child of your uncle or aunt.
• In-laws: Relations by marriage.
  • Father-in-law: Spouse’s father.
  • Mother-in-law: Spouse’s mother.
  • Brother-in-law: Spouse’s brother, Sister’s husband, or Brother’s wife’s brother.
  • Sister-in-law: Spouse’s sister, Brother’s wife, or Sister’s husband’s sister.
  • Son-in-law: Daughter’s husband.
  • Daughter-in-law: Son’s wife.

Representing Relationships (Family Tree Diagrams):

Drawing a family tree is the most effective way to solve these problems. Use consistent symbols:

• Male: Square (□)
• Female: Circle (∘)
• Siblings: Horizontal line between them (e.g., □−∘)
• Married Couple: Double horizontal line between them (e.g., □=∘)
• Parent-Child: Vertical line from parent to child (e.g., □ or ∘ above □ or ∘)
• Same Generation: Horizontal placement.
• Different Generations: Vertical placement.

Types of Blood Relation Problems:

Let’s explore the common categories with plenty of examples.

Type 1: Dialogue/Conversation-Based Problems

These problems involve a person introducing or pointing to another person, describing their relationship.

• Example 1: Pointing to a man, a woman said, “His mother is the only daughter of my mother.” How is the man related to the woman?
  • My mother’s only daughter = Myself.
  • So, “His mother is me.”
  • Answer: Son (The man is the woman’s son)
• Example 2: Introducing a boy, a girl said, “He is the son of the daughter of the father of my uncle.” How is the boy related to the girl?
  • Father of my uncle = My grandfather.
  • Daughter of my grandfather = My aunt or my mother.
  • Son of my aunt = My cousin. Son of my mother = My brother.
  • Assuming a common scenario (not mother), “He is my cousin’s son.” No, “He is the son of my aunt”. So, he is her cousin.
  • Answer: Cousin (The boy is the girl’s cousin)
• Example 3: Pointing to a photograph, a person says, “I have no brother or sister, but that man’s father is my father’s only son.” Whose photograph was it?
  • My father’s only son = Myself (since I have no brother or sister).
  • “That man’s father is me.”
  • Answer: His own son’s (The photograph was of his son)
• Example 4: A man tells a woman, “Your mother’s husband’s sister is my aunt.” How is the man related to the woman?
  • Your mother’s husband = Your father.
  • Your father’s sister = Your aunt.
  • “Your aunt is my aunt.” This means they share the same aunt.
  • They could be siblings or cousins. Since the question asks “how is the man related to the woman,” the simplest direct relation is sibling if they share the same parents, or cousin if it’s the same aunt from a different parent.
  • More precisely, if her aunt is his aunt, then his father is her father’s brother, or his mother is her mother’s sister/brother’s wife. This means they are cousins.
  • Answer: Cousin (The man is the woman’s cousin)
• Example 5: Looking at a portrait of a man, Harsh says, “His mother is the wife of my grandfather’s only son.” How is Harsh related to the man in the portrait?
  • My grandfather’s only son = My father.
  • Wife of my father = My mother.
  • “His mother is my mother.” This means they share the same mother.
  • Answer: Brother (Harsh is the man’s brother)
• Example 6: Anil says, “This girl is the wife of the grandson of my mother.” Who is Anil to the girl?
  • Grandson of my mother = My son (if I’m male) or My brother’s son (if I’m female).
  • If grandson is “my son,” then “This girl is the wife of my son.”
  • Answer: Father-in-law (Anil is the girl’s father-in-law)
• Example 7: Rahul says to a lady, “Your father’s only son is my father.” How is the lady related to Rahul?
  • Your father’s only son = Your brother.
  • “Your brother is my father.”
  • Answer: Aunt (The lady is Rahul’s aunt)
• Example 8: Introducing a man, a woman says, “His wife is the only daughter of my father.” How is the woman related to the man?
  • My father’s only daughter = Myself.
  • “His wife is me.”
  • Answer: Wife (The woman is the man’s wife)
• Example 9: Pointing to a photograph, a man tells his friend, “She is the daughter of the only son of my father’s wife.” How is the girl in the photograph related to the man?
  • My father’s wife = My mother.
  • Only son of my mother = Myself.
  • “She is the daughter of me.”
  • Answer: Daughter (The girl is the man’s daughter)
• Example 10: If A is the brother of B, B is the sister of C, and C is the father of D, how is D related to A?
  • A, B, C are siblings. C is D’s father.
  • D is C’s child. C is A’s sibling.
  • Answer: Niece or Nephew (D is A’s niece or nephew, gender unknown)

Type 2: Puzzle-Based Problems (Family Tree Construction)

These problems provide a paragraph describing relationships between multiple people. You need to construct a family tree to answer the questions.

Common Family Tree Scenario 1 (Examples 11-15): In a family, there are six members: A, B, C, D, E, and F.

• A and B are a married couple.
• A is the father of C.
• C is the mother of D.
• F is the brother of D.
• E is the daughter of B.

Let’s draw the family tree: A (□) = B (∘) | C (∘) – E (∘) (siblings) | D (gender unknown) – F (□) (siblings)

• Example 11: How is F related to C?
  • Answer: Son (F is C’s son)
• Example 12: How is E related to D?
  • Answer: Aunt (E is D’s maternal aunt)
• Example 13: How many female members are there in the family?
  • B (∘), C (∘), E (∘). D’s gender is unknown.
  • Answer: At least 3 (B, C, E)
• Example 14: If G is the husband of C, how is G related to B?
  • C is B’s daughter. G is C’s husband.
  • Answer: Son-in-law (G is B’s son-in-law)
• Example 15: How is B related to F?
  • B is F’s grandmother.
  • Answer: Grandmother

Common Family Tree Scenario 2 (Examples 16-20):

• P is the father of Q.
• R is the son of S.
• S is the daughter of P.
• T is the wife of P.
• U is the mother of T.

Let’s draw the family tree: U (∘) | P (□) = T (∘) | S (∘) – Q (gender unknown) (siblings) | R (□)

• Example 16: How is R related to P?
  • Answer: Grandson (R is P’s grandson)
• Example 17: How is Q related to S?
  • Answer: Brother or Sister (Q is S’s brother or sister)
• Example 18: How is T related to R?
  • Answer: Grandmother (T is R’s grandmother)
• Example 19: If V is the wife of Q, how is V related to S?
  • Answer: Sister-in-law (V is S’s sister-in-law)
• Example 20: How is U related to S?
  • Answer: Grandmother (U is S’s maternal grandmother)

Common Family Tree Scenario 3 (Examples 21-25):

• L is the brother of M.
• N is the sister of O.
• M is the daughter of P.
• Q is the son of O.
• R is the father of P.
• S is the wife of R.

Let’s draw the family tree: S (∘) = R (□) | P (gender unknown) | L (□) – M (∘) – N (∘) – O (gender unknown) (siblings, but M is daughter of P, L is brother of M. N is sister of O. Q is son of O. So L, M, N, O are likely siblings) | Q (□)

Correction for tree structure: S (∘) = R (□) | P (gender unknown) | L (□) – M (∘) – N (∘) – O (gender unknown) (Siblings) | Q (□) (Q is O’s child)

• Example 21: How is L related to Q?
  • Answer: Uncle (L is Q’s maternal/paternal uncle, depending on O’s gender)
• Example 22: How is P related to Q?
  • Answer: Grandparent (P is Q’s grandparent)
• Example 23: How is S related to M?
  • Answer: Grandmother (S is M’s grandmother)
• Example 24: If N is female, how is N related to Q?
  • Answer: Aunt (N is Q’s aunt)
• Example 25: If R is the maternal grandfather of Q, what is the gender of P?
  • R is Q’s maternal grandfather, meaning R is O’s mother’s father. So P must be O’s mother and thus female.
  • Answer: Female

Type 3: Coded Relations Problems

In this type, relationships are represented by symbols. You need to decode the symbols to find the relationship.

Coding Scheme 1 (Examples 26-30):

• A + B means A is the father of B.
• A – B means A is the mother of B.
• A × B means A is the brother of B.
• A ÷ B means A is the sister of B.
• A = B means A is the husband of B.
• Example 26: If P + Q – R, then how is P related to R?
  • P is father of Q. Q is mother of R.
  • P is father of Q, Q is mother of R. So P is R’s father’s father (Paternal Grandfather).
  • Answer: Paternal Grandfather
• Example 27: If L × M = N, then how is N related to L?
  • L is brother of M. M is husband of N. So N is M’s wife.
  • L is M’s brother, and N is M’s wife. So N is L’s sister-in-law.
  • Answer: Sister-in-law
• Example 28: Which of the following means C is the daughter of A?
  • A – B + C (∘) (A is mother of B, B is father of C. So A is C’s grandmother).
  • A + B – C (∘) (A is father of B, B is mother of C. So A is C’s grandfather).
  • A – C ÷ B (A is mother of C. C is sister of B. So C is A’s daughter).
  • Answer: A – C ÷ B
• Example 29: If X ÷ Y + Z, how is Z related to X?
  • X is sister of Y. Y is father of Z.
  • X is Z’s father’s sister.
  • Answer: Aunt
• Example 30: If D = E × F, how is E related to D?
  • D is husband of E. E is brother of F.
  • E is D’s wife, and E is brother of F.
  • Answer: Wife

Coding Scheme 2 (Examples 31-35):

• P @ Q means P is the mother of Q.
• P # Q means P is the father of Q.
• P $ Q means P is the brother of Q.
• P * Q means P is the sister of Q.
• Example 31: What does A # B @ C mean?
  • A is father of B. B is mother of C.
  • A is C’s paternal grandfather.
  • Answer: A is C’s Paternal Grandfather
• Example 32: In the expression A @ B # C, how is C related to A?
  • A is mother of B. B is father of C.
  • C is A’s son’s child.
  • Answer: Grandson or Granddaughter (C’s gender is unknown)
• Example 33: Which expression means F is the daughter of E?
  • E # F * G (E is father of F. F is sister of G. So F is E’s daughter).
  • E @ F # G (E is mother of F. F is father of G. So F is E’s son).
  • Answer: E # F * G
• Example 34: If X $ Y * Z, then how is X related to Z?
  • X is brother of Y. Y is sister of Z.
  • X, Y, Z are siblings.
  • Answer: Brother
• Example 35: If P @ Q $ R, then how is P related to R?
  • P is mother of Q. Q is brother of R.
  • P is Q’s mother. Q is R’s brother. So P is R’s mother.
  • Answer: Mother

Coding Scheme 3 (Examples 36-40):

• A + B means A is the daughter of B.
• A – B means A is the son of B.
• A × B means A is the wife of B.
• A ÷ B means A is the husband of B.
• Example 36: If P × Q – R, how is R related to P?
  • P is wife of Q. Q is son of R.
  • Q is R’s son. P is Q’s wife. So P is R’s daughter-in-law. R is P’s father-in-law or mother-in-law.
  • Answer: Father-in-law or Mother-in-law (R’s gender is unknown)
• Example 37: What does L ÷ M + N mean?
  • L is husband of M. M is daughter of N.
  • M is N’s daughter. L is M’s husband. So L is N’s son-in-law.
  • Answer: L is N’s Son-in-law
• Example 38: Which expression shows that D is the mother of C?
  • C – D + E (C is son of D. D is daughter of E. So D is mother of C).
  • C + D × E (C is daughter of D. D is wife of E. So D is mother of C).
  • Answer: C + D × E (More direct route) or C – D + E
• Example 39: If A + B × C, then how is C related to A?
  • A is daughter of B. B is wife of C.
  • B is C’s wife. A is B’s daughter. So A is C’s daughter. C is A’s father.
  • Answer: Father
• Example 40: If X × Y – Z, how is Z related to X?
  • X is wife of Y. Y is son of Z.
  • Y is Z’s son. X is Y’s wife. So X is Z’s daughter-in-law. Z is X’s father-in-law or mother-in-law.
  • Answer: Father-in-law or Mother-in-law

Mixed Practice (More Examples to reach 50+):

• Example 41: My mother is the only daughter of your father. How are we related?
  • Answer: You are my maternal grandfather/grandmother (depending on gender). I am your grandchild.
• Example 42: X’s father is Y’s father’s only son. How are X and Y related?
  • Y’s father’s only son = Y. So, X’s father is Y.
  • Answer: Y is X’s father.
• Example 43: Introducing a girl, a boy said, “Her mother is the only daughter of my mother-in-law.” How is the boy related to the girl?
  • My mother-in-law’s only daughter = My wife (if male) or My husband’s sister (if female).
  • Assuming the boy is male, his mother-in-law’s only daughter is his wife.
  • So, “Her mother is my wife.”
  • Answer: Father (The boy is the girl’s father)
• Example 44: In a family of 7 members: P, Q, R, S, T, U, V. P is the father of Q. R is the mother of S. Q is the brother of S. T is the husband of V. U is the daughter of T. S is the wife of V. How is U related to P?
  • P (□)
  • |
  • Q (□) – S (∘) (siblings) = V (gender unknown, but V is S’s husband, so V is □)
  • |
  • U (∘)
  • U is the daughter of T. T is husband of V. This means T and V are a married couple. But S is V’s wife.
  • Correction for input consistency: Let’s assume S is the wife of T.
  • P (□)
  • |
  • Q (□) – S (∘) = T (□) (siblings)
  • |
  • U (∘)
  • U is S’s daughter. S is P’s daughter.
  • Answer: Granddaughter (U is P’s granddaughter)
• Example 45: A is the son of C. C and Q are siblings. Q has a daughter R and a son T. T is married to U. How is U related to Q?
  • C – Q (siblings)
  • |
  • A (C’s son) R (Q’s daughter) – T (Q’s son) = U (T’s wife)
  • U is the wife of Q’s son.
  • Answer: Daughter-in-law
• Example 46: P is the father of Q. R is the sister of Q. S is the mother of P. T is the brother of S. How is R related to T?
  • S (∘) – T (□) (siblings)
  • |
  • P (□)
  • |
  • Q (gender unknown) – R (∘) (siblings)
  • R is P’s daughter. P is T’s brother. So P is T’s nephew/niece’s father.
  • Answer: Niece (R is T’s niece)
• Example 47: My brother’s father’s only daughter’s husband is my ________.
  • My brother’s father = My father.
  • My father’s only daughter = My sister.
  • My sister’s husband = My brother-in-law.
  • Answer: Brother-in-law
• Example 48: If S is the son of R, P is the brother of R, Q is the sister of S, and T is the father of P. How is Q related to T?
  • T (□)
  • |
  • P (□) – R (gender unknown) (siblings)
  • |
  • S (□) – Q (∘) (siblings)
  • Q is R’s child. R is T’s child. So Q is T’s grandchild.
  • Answer: Granddaughter
• Example 49: Pointing to a girl, Amit said, “She is the only daughter of my mother’s husband’s daughter.” How is Amit related to the girl?
  • My mother’s husband = My father.
  • My father’s daughter = My sister.
  • “She is the only daughter of my sister.”
  • Answer: Uncle (Amit is the girl’s maternal uncle)
• Example 50: A is B’s mother. B is C’s brother. D is C’s father. How is D related to A?
  • A (∘)
  • |
  • B (□) – C (gender unknown) (siblings)
  • D (□) is C’s father. Since A is B’s mother, and B & C are siblings, A is also C’s mother.
  • If A is C’s mother and D is C’s father, then A and D are married.
  • Answer: Husband (D is A’s husband)
• Example 51: A is B’s sister. C is B’s mother. D is C’s father. E is D’s mother. How is A related to D?
  • E (∘)
  • |
  • D (□)
  • |
  • C (∘)
  • |
  • A (∘) – B (gender unknown) (siblings)
  • A is C’s daughter. C is D’s daughter.
  • Answer: Granddaughter (A is D’s granddaughter)
• Example 52: If X is the husband of Y, Z is the father of Y, and W is the daughter of Z. How is W related to X?
  • Z (□)
  • |
  • Y (gender unknown) – W (∘) (siblings)
  • Y is Z’s child. W is Z’s daughter. So Y and W are siblings.
  • X is Y’s husband.
  • Answer: Sister-in-law (W is X’s sister-in-law)

Tips for Solving Blood Relation Problems:

1. Draw a Family Tree: This is by far the most effective method. Use the standard symbols to represent gender, marriage, and parent-child relationships.
2. Determine Gender: Carefully note the gender of each person. If the gender is not explicitly stated (e.g., “P is a child”), do not assume it. This is often a trick!
3. Break Down Complex Sentences: For dialogue-based questions, break down the statement from the end towards the beginning (e.g., “my mother’s only daughter” → “me”).
4. Use Generations: Place individuals on different levels to represent generations.
5. Re-verify: Once you have an answer, quickly trace the relationship on your diagram to ensure it holds true.
6. Practice Consistently: Familiarity with common family structures and quick identification of relationships comes with practice.