"Pointing to a photograph, a man said, 'She is the daughter of my grandfather's only son.' How is the woman related to the man?" Puzzles like this can tie your brain in knots — if you try to hold everything in your head. But there's a simple secret that makes them almost easy: draw a little family tree. Once the relationships are on paper, the answer becomes obvious. This chapter teaches you the diagram method and the family vocabulary you need, so blood-relation questions become quick, sure points.
Blood-relation questions describe a chain of family connections in words and ask how two people are related. They come in a few flavors: a straight description ("A is B's father, B is C's sister…"), a pointing/dialogue puzzle ("pointing to a man, she said…"), and a coded-relation version (where symbols stand for relationships). The fastest, most reliable method for all of them is to sketch a small family tree rather than juggling relations mentally.
On the Civil Service Exam, blood-relation items appear in Analytical Reasoning, usually 1 to 3 questions. They test careful reading and orderly diagramming — not cleverness — so a consistent method makes them dependable marks.
The difficulty is beginner to intermediate, rising with the length of the chain. The keys are to use simple diagram symbols, add each person as you read, know the family vocabulary (in-laws, maternal/paternal, cousins), and decode "pointing" puzzles from the speaker outward. This lesson builds each.
After completing this lesson you will be able to:
You should be comfortable with:
A quick refresher on the two building blocks of any family tree. A marriage links two people of the same generation (we'll draw it as a horizontal line, =). A parent-to-child link connects one generation to the next (a vertical line down, |). Every family relationship is built from these two connections plus gender (who is male or female). Keep "same-generation marriage" and "down-a-generation parenthood" in mind — the whole method rests on them.
Understanding family relationships and reasoning through chains is genuinely useful:
The exam tests blood relations because orderly, careful reasoning through a described structure is a core analytical skill.
Let's build the diagram method and the vocabulary.
Don't track relationships in your head; draw a family tree, adding each person as you read. Use simple, consistent symbols:
"A is B's father. B is C's sister. D is C's son. How is D related to A?" A is B's father → A is a parent, B is below A. B is C's sister → B and C are siblings (same level), both children of A. D is C's son → D is below C. So D is A's grandchild — specifically A's grandson.
Analogy: A family tree is a map. Trying to answer without drawing is like giving directions across a city from memory; sketching the map first makes the route obvious. Spend ten seconds drawing and the answer appears.
Process one statement at a time, placing each new person relative to those already drawn. Never jump ahead. By the end, the two people in the question are both on the tree, and you simply trace the path between them.
Know these exact terms — questions hinge on them:
Keep track of which generation each person is on. A common error is placing someone one level too high or low. Grandparent → parent → self → child → grandchild is a four-step ladder; count carefully as relationships chain.
In these, a speaker describes someone via a chain ("She is the daughter of my grandfather's only son"). Start from the speaker and work outward, one link at a time:
"She is the daughter of my grandfather's only son." My grandfather's only son = my father (assuming the speaker's father is the grandfather's only son). The daughter of my father = my sister (or the speaker herself, but "she" points to another person, so a sister). Answer: she is the speaker's sister.
Build the chain from "my" outward: grandfather → his only son → that son's daughter.
Some questions use symbols for relationships, e.g., "A + B means A is the father of B," "A − B means A is the wife of B," "A × B means A is the brother of B." Decode each symbol into a relationship, then diagram as usual. Always check the exact key given — symbols differ between questions.
A name or role doesn't always fix gender in these puzzles ("the doctor," "the engineer," a person referred to only by a letter). Use only the gender the puzzle states (through words like "he/she," "son/daughter," "father/mother"). Assuming gender is a classic error.
With the method set, let's picture, tabulate, and drill.
= marriage, | parent-to-child, □ male, ○ female — the toolkit for every tree.Blood relations use vocabulary and diagram rules:
| Relationship | Meaning |
|---|---|
| Sibling | shares a parent |
| Maternal / paternal | mother's side / father's side |
| Aunt/uncle | parent's sibling |
| Cousin | aunt/uncle's child |
| Nephew/niece | sibling's child |
| Brother/sister-in-law | spouse's sibling OR sibling's spouse |
| Son/daughter-in-law | child's spouse |
| Father/mother-in-law | spouse's parent |
| Grandparent/grandchild | two generations up/down |
Diagram symbols: = marriage (same generation); | parent to child (down a generation); mark gender; children below parents.
| When the question… | Do this… |
|---|---|
| gives a chain of relations | draw the tree sentence by sentence |
| says "pointing to… he/she said" | start from the speaker, chain outward |
| uses symbols (+, −, ×) for relations | decode with the given key, then diagram |
| asks "how is X related to Y" | trace the path between them on the tree |
| mentions "only son/daughter" | a strong clue narrowing the family |
| involves in-laws | apply the exact in-law definitions |
Step 1 — Set up symbols (= marriage, | parent-child) and read the first statement. ↓ Step 2 — Add each person to the tree, one sentence at a time, marking gender and generation. ↓ Step 3 — For pointing puzzles, start from the speaker and build the chain outward link by link. ↓ Step 4 — Trace the path between the two people in the question. ↓ Step 5 — Name the relationship precisely, checking gender and in-law status; don't assume unstated gender.
Why Step 2 matters most: placing people correctly as you read — right generation, right gender — is what makes the final trace trivial. Rushing the placement causes almost every error.
Example 1. A is the father of B. B is the son of C. How is C related to A? Thinking: A and C are both parents of B → they're spouses. Solution: C is A's wife (A father, C the other parent of B). Difficulty: ★☆☆☆☆
Example 2. P is Q's brother. Q is R's mother. How is P related to R? Thinking: P is Q's brother; Q is R's mother → P is R's uncle (mother's brother = maternal uncle). Solution: Uncle. Difficulty: ★★☆☆☆
Example 3 (grandchild). A is B's father. B is C's sister. D is C's son. How is D related to A? Solution: B and C are siblings (both A's children); D is C's son → D is A's grandson. Difficulty: ★★☆☆☆
Example 4 (in-law). X is married to Y. Z is Y's sister. How is Z related to X? Thinking: Z is the spouse's sister → sister-in-law. Solution: Z is X's sister-in-law. Difficulty: ★★☆☆☆
Example 5 (cousin). A and B are siblings. A's son is C; B's daughter is D. How are C and D related? Thinking: C and D are children of siblings → cousins. Solution: Cousins. Difficulty: ★★★☆☆
Example 6 (pointing puzzle). Pointing to a woman, a man said, "She is the daughter of my grandfather's only son." How is the woman related to the man? Thinking: Grandfather's only son = the man's father. The father's daughter = the man's sister. Solution: She is his sister. Difficulty: ★★★★☆
Example 7 (longer chain). A is B's mother. B is C's husband. C is D's mother. How is A related to D? Thinking: A is B's mother; B is C's husband; C is D's mother, and B (C's husband) is D's father. So A (B's mother) is D's paternal grandmother. Solution: Grandmother (paternal). Difficulty: ★★★★☆
Example 8 (coded). If "A + B" means A is the mother of B, and "A × B" means A is the brother of B, then in "P + Q × R," how is P related to R? Thinking: Q × R: Q is R's brother. P + Q: P is Q's mother. Since Q and R are siblings, P is also R's mother. Solution: P is R's mother. Difficulty: ★★★★☆
Example 9 (pointing, trickier). Pointing to a photograph, a woman said, "He is the son of the only son of my mother." How is the man in the photo related to the woman? Thinking: My mother's only son = the woman's brother. The son of my brother = my nephew. Solution: He is her nephew. Difficulty: ★★★★★
Example 10 (multi-generation). A is C's grandfather. B is C's father. D is B's brother. How is D related to A? Thinking: B is A's son (B is C's father, A is C's grandfather → A is B's father). D is B's brother → D is also A's son. Solution: D is A's son. Difficulty: ★★★★☆
Example 11 (in-law chain). M is N's father. N is married to O. P is O's father. How is M related to P? Thinking: M is N's father; O is N's spouse; P is O's father. M and P are the two fathers of a married couple — they are co-fathers-in-law (each is the other's balae in Filipino). Solution: They are fathers-in-law to each other (balae); M is the father-in-law of O, and P is the father-in-law of N. Difficulty: ★★★★★
Example 12 (avoid gender assumption). A is the child of B. C is the sister of A. Is C necessarily female, and how is C related to B? Thinking: "Sister" states C is female; C is a child of B (since C is A's sister and A is B's child) → C is B's daughter. Solution: Yes, "sister" fixes C as female; C is B's daughter. (Note: A's own gender was never stated — don't assume it.) Difficulty: ★★★★☆
Blood-relation puzzles yield easily to one habit: draw a family tree, adding each person sentence by sentence with simple symbols (= for marriage, | for parent-to-child), marking gender and generation. Know the exact vocabulary — siblings, in-laws (spouse's sibling or sibling's spouse), aunts/uncles, cousins, maternal/paternal, grandparents. For pointing puzzles, start from the speaker and chain outward ("my grandfather's only son…"); for coded puzzles, translate symbols into relationships first. Count generations carefully and never assume gender the puzzle doesn't state. Once the tree is drawn, the answer is simply the path between two people. Sketch, place carefully, trace — and these become quick, reliable points.
| Item | Key point |
|---|---|
| Method | draw the tree, add people one by one |
| Symbols | = marriage, ` |
| Sibling | shares a parent |
| In-law | spouse's sibling OR sibling's spouse |
| Aunt/uncle → cousin | parent's sibling → their child |
| Grandparent/grandchild | two generations |
| Pointing puzzle | start from the speaker, chain outward |
| Coded relation | decode the symbol key first |
| Gender | only as stated |
What's the best method for blood-relation questions? Draw a small family tree, adding each person as you read. Use = for marriage and a downward line for parent-to-child, and mark each person's gender and generation. Then trace the path between the two people in the question.
How do I solve "pointing to a photograph" puzzles? Start from the speaker ("my…") and work outward one relationship at a time. "My grandfather's only son" = my father; "the daughter of my father" = my sister, and so on.
What does "sister-in-law" cover? Two cases: your spouse's sister, and your sibling's wife. Both are sisters-in-law. The family tree shows which one a puzzle means.
How do I avoid generation mistakes? Place people on levels — grandparents on top, then parents, then children, then grandchildren. Counting rungs prevents the common off-by-one error (calling a grandchild a child, for instance).
Should I assume someone's gender from their name or role? No. Use only the gender the puzzle states through words like he/she, son/daughter, father/mother. Assuming gender is a frequent source of wrong answers.
Tick them all and blood-relation questions become quick, dependable points — and you'll untangle real family relationships with ease.
Put it to the test with 1,352 practice questions on this topic.