Blood Relations
CSAT · Logical Reasoning
Introduction
Blood-relation questions describe a family through a chain of statements and ask how two people are related. Drawing a small family tree – with generations in rows and genders marked – prevents almost every mistake.
Key concepts
Drawing conventions
- Use + or a square for male, − or a circle for female.
- Draw a horizontal double line for a married couple, a single horizontal line for siblings, a vertical line from parents to children.
- Keep each generation on one level.
Key relationship words
| Word | Meaning |
|---|---|
| Paternal / maternal | Father's side / mother's side |
| Uncle | Father's or mother's brother (or aunt's husband) |
| Aunt | Father's or mother's sister (or uncle's wife) |
| Nephew / niece | Son / daughter of one's brother or sister |
| Cousin | Child of an uncle or aunt |
| Brother-in-law | Spouse's brother or sister's husband |
| Sister-in-law | Spouse's sister or brother's wife |
| Father-in-law | Spouse's father |
Method
- Start from the person whose relation is asked about (the first name).
- Translate each statement into the tree one link at a time.
- Note genders only when a word reveals them – 'child' or 'sibling' do not.
- Read the final relation from the person asked about to the second person: 'How is A related to B?' means 'A is B's _'.
Coded relations
Some questions use symbols (A + B means A is the father of B, A × B means A is the wife of B …). Decode each symbol into a tree link and proceed in the same way.
- Generation up: parent → grandparent
- Same generation: sibling, cousin, spouse, in-laws
- Generation down: child → grandchild
- 'A is B's _' – always read from A to B
Solved examples
Example 1
A is the mother of F. F is the brother of N. How is A related to N?
(a) mother-in-law (b) sister (c) mother (d) daughter
- Follow the chain one link at a time: A is the mother of F. → F is the brother of N.
- A is female (from the word "mother").
- Combining the links, A is the mother of N. (Siblings are taken to share both parents.)
Answer: (c) mother
Example 2
W is the wife of D. D is the father of E. E is the wife of G. How is W related to G?
(a) niece (b) grandmother (c) mother-in-law (d) daughter-in-law
- Follow the chain one link at a time: W is the wife of D. → D is the father of E. → E is the wife of G.
- W is female (from the word "wife").
- Combining the links, W is the mother-in-law of G. (Siblings are taken to share both parents.)
Answer: (c) mother-in-law
Example 3
F is the wife of T. T is the father of Y. Y is the mother of N. How is F related to N?
(a) cousin (b) sister (c) daughter-in-law (d) grandmother
- Follow the chain one link at a time: F is the wife of T. → T is the father of Y. → Y is the mother of N.
- F is female (from the word "wife").
- Combining the links, F is the grandmother of N. (Siblings are taken to share both parents.)
Answer: (d) grandmother
Example 4
M is the mother of N. N is the husband of K. K is the mother of E. How is M related to E?
(a) niece (b) grandmother (c) granddaughter (d) mother
- Follow the chain one link at a time: M is the mother of N. → N is the husband of K. → K is the mother of E.
- M is female (from the word "mother").
- Combining the links, M is the grandmother of E. (Siblings are taken to share both parents.)
Answer: (b) grandmother
Example 5
G is the mother of H. H is the son of P. P is the father of F. How is G related to F?
(a) mother (b) daughter-in-law (c) grandmother (d) daughter
- Follow the chain one link at a time: G is the mother of H. → H is the son of P. → P is the father of F.
- G is female (from the word "mother").
- Combining the links, G is the mother of F. (Siblings are taken to share both parents.)
Answer: (a) mother
Example 6
M is the sister of P. P is the son of U. How is M related to U?
(a) cousin (b) daughter (c) daughter-in-law (d) mother
- Follow the chain one link at a time: M is the sister of P. → P is the son of U.
- M is female (from the word "sister").
- Combining the links, M is the daughter of U. (Siblings are taken to share both parents.)
Answer: (b) daughter
Example 7
S is the daughter of J. J is the wife of P. How is S related to P?
(a) mother-in-law (b) cousin (c) niece (d) daughter
- Follow the chain one link at a time: S is the daughter of J. → J is the wife of P.
- S is female (from the word "daughter").
- Combining the links, S is the daughter of P. (Siblings are taken to share both parents.)
Answer: (d) daughter
Example 8
E is the daughter of N. N is the father of X. How is E related to X?
(a) sister (b) sister-in-law (c) aunt (d) mother
- Follow the chain one link at a time: E is the daughter of N. → N is the father of X.
- E is female (from the word "daughter").
- Combining the links, E is the sister of X. (Siblings are taken to share both parents.)
Answer: (a) sister
- Mark gender as soon as a word reveals it.
- If a gender is never revealed, options that require a gender can be eliminated.
- Count generations between the two people first – it removes most options.
- Reversing the direction of the relation (son vs father).
- Assuming the gender of a person described only as 'child' or 'sibling'.
- Confusing 'only son of my grandfather' (my father or uncle) with my brother.
Practice set
Attempt all 12 questions (about 90 seconds each), then check the worked solutions below.
Q1. A is the daughter of K. K is the sister of G. How is A related to G?
(a) daughter-in-law (b) mother (c) niece (d) cousin
Q2. T is the mother of C. C is the sister of F. F is the daughter of V. How is T related to V?
(a) wife (b) sister (c) aunt (d) granddaughter
Q3. U is the sister of B. B is the son of M. M is the wife of C. How is U related to C?
(a) daughter (b) wife (c) mother (d) niece
Q4. S is the son of E. E is the mother of T. How is S related to T?
(a) son (b) father (c) brother (d) husband
Q5. M is the wife of P. P is the brother of Y. How is M related to Y?
(a) granddaughter (b) mother (c) sister-in-law (d) wife
Q6. Z is the son of X. X is the husband of G. How is Z related to G?
(a) brother (b) son (c) uncle (d) father
Q7. G is the father of Q. Q is the daughter of S. How is G related to S?
(a) father (b) grandfather (c) brother (d) husband
Q8. M is the son of Z. Z is the mother of K. K is the father of R. How is M related to R?
(a) father-in-law (b) uncle (c) father (d) cousin
Q9. S is the son of V. V is the husband of F. How is S related to F?
(a) father-in-law (b) grandson (c) uncle (d) son
Q10. P is the brother of V. V is the daughter of T. How is P related to T?
(a) brother (b) father-in-law (c) father (d) son
Q11. J is the mother of X. X is the sister of D. D is the son of P. How is J related to P?
(a) wife (b) sister-in-law (c) mother (d) granddaughter
Q12. Z is the sister of S. S is the son of E. E is the husband of T. How is Z related to T?
(a) mother (b) daughter (c) daughter-in-law (d) grandmother
Q1 – (c) niece. Follow the chain one link at a time: A is the daughter of K. → K is the sister of G. A is female (from the word "daughter"). Combining the links, A is the niece of G. (Siblings are taken to share both parents.)
Q2 – (a) wife. Follow the chain one link at a time: T is the mother of C. → C is the sister of F. → F is the daughter of V. T is female (from the word "mother"). Combining the links, T is the wife of V. (Siblings are taken to share both parents.)
Q3 – (a) daughter. Follow the chain one link at a time: U is the sister of B. → B is the son of M. → M is the wife of C. U is female (from the word "sister"). Combining the links, U is the daughter of C. (Siblings are taken to share both parents.)
Q4 – (c) brother. Follow the chain one link at a time: S is the son of E. → E is the mother of T. S is male (from the word "son"). Combining the links, S is the brother of T. (Siblings are taken to share both parents.)
Q5 – (c) sister-in-law. Follow the chain one link at a time: M is the wife of P. → P is the brother of Y. M is female (from the word "wife"). Combining the links, M is the sister-in-law of Y. (Siblings are taken to share both parents.)
Q6 – (b) son. Follow the chain one link at a time: Z is the son of X. → X is the husband of G. Z is male (from the word "son"). Combining the links, Z is the son of G. (Siblings are taken to share both parents.)
Q7 – (d) husband. Follow the chain one link at a time: G is the father of Q. → Q is the daughter of S. G is male (from the word "father"). Combining the links, G is the husband of S. (Siblings are taken to share both parents.)
Q8 – (b) uncle. Follow the chain one link at a time: M is the son of Z. → Z is the mother of K. → K is the father of R. M is male (from the word "son"). Combining the links, M is the uncle of R. (Siblings are taken to share both parents.)
Q9 – (d) son. Follow the chain one link at a time: S is the son of V. → V is the husband of F. S is male (from the word "son"). Combining the links, S is the son of F. (Siblings are taken to share both parents.)
Q10 – (d) son. Follow the chain one link at a time: P is the brother of V. → V is the daughter of T. P is male (from the word "brother"). Combining the links, P is the son of T. (Siblings are taken to share both parents.)
Q11 – (a) wife. Follow the chain one link at a time: J is the mother of X. → X is the sister of D. → D is the son of P. J is female (from the word "mother"). Combining the links, J is the wife of P. (Siblings are taken to share both parents.)
Q12 – (b) daughter. Follow the chain one link at a time: Z is the sister of S. → S is the son of E. → E is the husband of T. Z is female (from the word "sister"). Combining the links, Z is the daughter of T. (Siblings are taken to share both parents.)
- Draw a tree: generations in rows
- Read 'A is B's _'
- Gender only from gendered words
- Count generations first
