Blood Relations

Blood Relations

🟢 Lite — Quick Review (1h–1d)

Rapid summary for last-minute revision before your exam.

Blood Relations — Quick Facts

Key Terminology:

• Father’s son = brother or “myself” (if male speaking)
• Mother’s daughter = sister or “myself” (if female speaking)
• Brother’s sister = sister (not necessarily “me”)
• Sister’s brother = brother
• Maternal = mother’s side (related through mother)
• Paternal = father’s side (related through father)

Generation Mapping:

• Your parent’s sibling = your aunt/uncle
• Your grandparent = parent’s parent
• Your sibling’s child = your niece/nephew
• Your sibling = brother or sister (share at least one parent)

Common Relationship Phrases:

Phrase	Meaning
”Only son of father”	There are no other sons
”Married to”	Spouse relation
”Only child”	No siblings at all
”Grandmother’s only child”	One parent (either mother or father)
“Second daughter”	Two daughters total, this is the second

⚡ CAT Exam Tip: Draw a family tree diagram. Start with the subject, draw their generation, then parents, then siblings’ families. This visual approach prevents confusion in complex blood relation problems.

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🟡 Standard — Regular Study (2d–2mo)

For students who want genuine understanding.

Blood Relations — Study Guide

Interpreting Relationship Puzzles:

Example: “A is the brother of B. B is the sister of C. C is the father of D. How is A related to D?”

Step-by-step:

1. A and B are siblings (brother-sister pair)
2. B is sister of C → C is a sibling of B, and therefore also a sibling of A
3. C is father of D
4. Since A is a sibling of C, and C is D’s parent, A is D’s uncle or aunt

Because A is described as a “brother,” A is male, so A is D’s uncle.

Example: “Pointing to a man, a woman said, ‘His mother is the only daughter of my mother.’ How is the woman related to the man?”

Resolve the innermost phrase first: “the only daughter of my mother” is the woman herself, since she is the one and only daughter of her own mother. The statement therefore equates “his mother” with the woman:

• “His mother” = the only daughter of “my mother”
• The only daughter of “my mother” = the woman (the speaker)
• Therefore “his mother” = the woman

Answer: The woman is the man’s mother.

Coded Blood Relations:

In some CAT questions, relationships are coded with symbols:

• A + B means A is B’s sister
• A − B means A is B’s brother
• A × B means A is B’s mother
• A ÷ B means A is B’s father

Example: If P + Q means “P is Q’s sister,” Q is the son of R, and P + R means P is R’s daughter, what is R to Q?

• Q is the son of R → R is Q’s parent
• P is Q’s sister and P is R’s daughter → P and Q are both children of R

Since the code specifies no gender for R, R is simply Q’s parent. (R could be father or mother; coded questions only state what the symbols define.)

⚡ Common Student Mistake: Misinterpreting “only” — “only son of X” means there is exactly one male child, not “the sole surviving child.”

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🔴 Extended — Deep Study (3mo+)

Comprehensive coverage for students on a longer study timeline.

Blood Relations — Comprehensive Notes

Complex Family Tree Analysis:

Example Problem:

“A is married to B. B is the mother of C. C is married to D. D is the father of E. F is the son of C. G is the grandmother of F. G is married to H. H is the father of I. I is the sibling of F. J is the son of I.”

Find: (a) How is A related to F? (b) Who is J’s uncle?

Solution:

Work through each statement systematically and label every person by generation:

1. B is mother of C.
2. A is married to B → A is B’s husband, so A is the father of C.
3. C is married to D → D is C’s spouse.
4. D is father of E → E is a child of C and D.
5. F is son of C → C is F’s parent.
6. I is sibling of F → I is also a child of C.
7. H is father of I → since I is C’s child, H is the father of C (i.e., H and B are C’s parents).
8. G is married to H, and G is the grandmother of F → G is B’s mother and C’s mother’s… here G is the parent of B, making G and H the maternal grandparents of C. Reconciling statement 7, H and B are C’s parents and G is B’s mother; G is grandmother of F because F is C’s child.
9. J is son of I → J is C’s grandchild.

This yields a consistent three-generation tree:

        G ── married to ── H
                 │
        (parents of B; G is grandmother of F)
                 │
        A ── married to ── B
                 │
              (parents of C)
                 │
        C ── married to ── D
                 │
          (parents of F, I, E)
            ┌────┴────┐
            F         I
                      │
                      J  (son of I)

Answers:

(a) A is the father of C, and C is the parent of F, so A is the grandfather of F.

(b) J is the son of I. I’s siblings are F and E (all children of C). The brother of I’s parent or the brother of I serves as J’s uncle: F is I’s brother, and J is I’s son, so F is J’s uncle.

CAT Pattern Analysis (2015–2024):

• 2015: Direct relationship identification
• 2017: Multi-generation family tree
• 2019: Coded relationship symbols
• 2021: “Only” and “married to” combinations
• 2023: Complex multi-step relationships
• 2024: Family with multiple siblings and in-laws

⚡ Exam Strategy: In complex problems, assign generation levels (G1 = oldest, G2 = parents, G3 = siblings, G4 = children). Work from known relationships downward, labeling each person as you go. If a relationship cannot be determined (e.g., gender not specified), note the ambiguity.