SSC CGL Reasoning · Blood Relations
Direct Relations
Short chains of plain statements such as 'A is the brother of B. B is the son of C', solved by placing each person on a small family tree, one statement at a time.
Why this matters
Thirty-five questions in the bank, thirty-three of them from the 2025 shifts and all but two EASY. Each is one to four short statements in order, so a tree drawn as you read gives the answer in a few seconds; the marks are lost on a skipped sibling step or a gender nobody stated.
Concept 1 of 4: Counting generations up and down a family tree
Every relation sits on a level. Your parents are one level above you, their parents two above, your children one below. A married couple stands on one level and shares the children below it. Once each person has a level, the relation word is just the number of levels plus a gender.
Definition
- Write each statement as one link. 'A is the daughter of B' puts B one level above A, and A is female.
- One level up is a father or mother; two up is a grandfather or grandmother; three up is a great-grandparent.
- One level down is a son or daughter; two down is a grandson or granddaughter.
- The father's side is paternal and the mother's side is maternal: the mother's mother is the maternal grandmother.
- A husband and wife stand on the same level. SSC treats a married couple as the parents of the same children, so 'D is the wife of C' and 'B is the son of C' make D the mother of B.
- Fast route: count the levels between the two people and add the gender of the person asked about. Two levels up and female is grandmother, whatever the path.
Worked example
P is the son of Q. Q is the daughter of R. How is P related to R?
Practice this conceptself-check · 4 quick reps
The same idea in a real exam question:
SSC CGL · 2025 · Tier I, 16 Sep 2025, Shift 1 · Q14Easy
Example 1 · Blood Relations · Direct Relations
A is the daughter of B. B is the son of C. D is the wife of C. How is D related to A?
Answering the relation the wrong way round
'How is A related to B?' asks what A is to B. If B turns out to be A's grandmother, the answer is grandson or granddaughter, not grandmother. Say the answer as a sentence, 'A is B's ...', before you pick it.
Calling every grandmother paternal
The mother's mother is the maternal grandmother; only the father's mother is paternal. When the options print both, follow the middle person: through a mother is maternal, through a father is paternal.
Concept 2 of 4: Siblings share the same parents
A brother or sister link joins two people on the same level who have the same parents. So anything you learn about one sibling's parents is true for every sibling. Most statement chains turn on this one step.
Definition
- 'A is the brother of B' means A and B have the same parents, and A is male. It says nothing about B's gender.
- A parent of one sibling is a parent of all of them: 'A is the brother of B' and 'B is the son of C' make A the son of C.
- Sibling links chain: if A is the brother of B, B the sister of C and C the brother of D, all four are siblings.
- 'P is the father of Q and R' makes Q and R siblings.
- Fast route: draw siblings on one horizontal line. Any line up to a parent, drawn from one of them, is drawn from all of them.
Worked example
F is the daughter of G. G is the sister of H. J is the father of H. How is J related to F?
Practice this conceptself-check · 4 quick reps
The same idea in a real exam question:
SSC CGL · 2025 · Tier I, 16 Sep 2025, Shift 2 · Q5Easy
Example 2 · Blood Relations · Direct Relations
B is the sister of A. A is the brother of C. C is the daughter of D. How is B related to D?
Treating a sibling's wife as a sibling
If A is the brother of B and C is the wife of B, C is not A's sister. She married into the family on B's level, so she is A's brother's wife, a sister-in-law.
Stopping one step early
From 'A is the brother of B, B is the son of C', the answer to 'How is A related to C?' is son. A student who stops at 'brother of B' never moves A up to C and picks a wrong relation such as nephew.
Concept 3 of 4: Uncles, aunts, nephews, nieces and cousins
These are the side branches of the tree: the brothers and sisters of your parents, and their children. Each one is a sibling step joined to a parent step, so you already have the tools; only the names are new.
Definition
- Uncle: the brother of a parent, or the husband of an aunt. Aunt: the sister of a parent, or the wife of an uncle.
- The father's brother is the paternal uncle; the mother's brother is the maternal uncle. The same rule names aunts.
- Nephew or niece: the son or daughter of your brother or sister (or of your husband's or wife's brother or sister).
- Cousin: the child of an uncle or aunt. A cousin is on your own level; an uncle is one level up; a nephew one level down.
- Elimination: when the asked person's gender is not given and only one of 'uncle' and 'aunt' is printed, SSC keys the one printed. Check the level first; it removes most options.
Worked example
P is the sister of Q. Q is the father of R. How is P related to R?
Practice this conceptself-check · 4 quick reps
The same idea in a real exam question:
SSC CGL · 2025 · Tier I, 15 Sep 2025, Shift 1 · Q21Easy
Example 3 · Blood Relations · Direct Relations
A is the brother of B. C is the father of A. D is the brother of C. E is the son of D. How is E related to B?
Putting a cousin on the wrong level
A cousin is on your own level, not one above or below. Your uncle's son is your cousin; your cousin's son is one level below you, so he is not your cousin.
Mixing paternal and maternal uncles
The mother's brother is the maternal uncle, the father's brother the paternal uncle. SSC often prints both, so name the parent in the middle before you answer.
Concept 4 of 4: When a gender is fixed, and when the answer cannot be determined
A relation word carries a gender only for the person it describes. Some answers need a gender that no statement gives, and then the honest answer is that it cannot be told. SSC prints that option on purpose.
Definition
- Words that make a person male: son, brother, father, husband, nephew, uncle, grandson. Female: daughter, sister, mother, wife, niece, aunt, granddaughter.
- The word fixes only the person on its left: 'A is the son of B' makes A male and says nothing about B.
- A 'not' can fix a gender: if A is the father of B but B is not A's son, B is a daughter.
- If the answer needs a gender that no statement gives and 'Cannot be determined' is printed, that is the answer, even when 'grandfather' is printed too.
- If no such option is printed, choose the word that needs no gender: grandparent, sibling, cousin.
Worked example
L is the son of M. M is the daughter of N. (a) How is L related to N? (b) How is N related to L?
Practice this conceptself-check · 4 quick reps
The same idea in a real exam question:
SSC CGL · 2025 · Tier I, 13 Sep 2025, Shift 3 · Q21Moderate
Example 4 · Blood Relations · Direct Relations
P's brother is Q. Q is the father of R. R is the sister of S. How is S related to P?
Taking a gender from the word on the right
'A is the son of B' tells you A is male. It does not make B the father: B may be the mother. Only a word with B on its left fixes B.
Skipping a printed 'Cannot be determined'
When the asked person's gender appears in no statement, 'Cannot be determined' is the correct option, even if 'grandfather' or 'nephew' is printed beside it. Picking the likely gender is a guess, not a deduction.
Summary — formulas & gotchas at a glance
A revision cheat-sheet for the formulas and gotchas above. Click any concept name to jump back to its full explanation.
Watch out for (8)
- Answering the relation the wrong way round→ Counting generations up and down a family tree
- Calling every grandmother paternal→ Counting generations up and down a family tree
- Treating a sibling's wife as a sibling→ Siblings share the same parents
- Stopping one step early→ Siblings share the same parents
- Putting a cousin on the wrong level→ Uncles, aunts, nephews, nieces and cousins
- Mixing paternal and maternal uncles→ Uncles, aunts, nephews, nieces and cousins
- Taking a gender from the word on the right→ When a gender is fixed, and when the answer cannot be determined
- Skipping a printed 'Cannot be determined'→ When a gender is fixed, and when the answer cannot be determined
Test yourself on Blood Relations
20 past SSC CGL questions from this chapter, timed at 12 minutes and marked the way the exam marks it. You see your score and every answer the moment you finish. Free to start.