Blood relations for SSC CHSL

Blood relation questions read like riddles, and that is the problem. Holding four relationships in your head while you read the fifth is where candidates go wrong. Drawn on paper, the same question becomes a small diagram you can read the answer off.

So the one habit that matters is to draw as you read, one statement at a time. The second habit is to be strict about gender: use only what the question tells you, and nothing a name or a sentence seems to suggest.

How it is asked

• Chain questions: a string of statements, then "How is A related to D?"
• Pointing or introducing: "Pointing to a photograph, a woman says…"
• Coded relations: "A # B means A is the father of B…", followed by an expression to decode, or a relation to encode.
• Family puzzles: a short paragraph about a family of six or eight, with several questions on it.

The words you need

"Paternal" means on the father's side and "maternal" on the mother's side. A paternal aunt is the father's sister.

Drawing the tree

• Generations on levels. Grandparents at the top, then parents, then children.
• Lines: a vertical line for parent and child, a horizontal line for siblings, and a double line (or =) for a married couple.
• Gender marks: + for male and − for female, or a square and a circle. Mark a gender only when a word in the question gives it: brother, sister, son, daughter, father, mother, husband, wife, he, she, man, woman.
• Unknown gender: leave the person unmarked. If the final answer depends on that gender, the answer is "cannot be determined".

The standard convention is that siblings share both parents and a married couple are the parents of their children, unless the question says otherwise.

The method, step by step

1. Put the first person on the page.
2. Add each new person on the right level, with the right line.
3. Mark genders from the words in the question only.
4. When the question asks "How is A related to D?", start at D and describe A from D's point of view: A is D's _____.
5. If the answer needs a gender you never marked, choose "cannot be determined" if it is an option.

Six worked questions

Q1. A is the brother of B. B is the daughter of C. D is the father of C. How is A related to D? (a) Son (b) Grandson (c) Nephew (d) Cannot be determined
A and B are C's children. D is C's father, one level above. A is male ("brother"). So A is D's grandson. C's gender is not given, and it is not needed. Answer: (b) Grandson.

Q2. P is the mother of Q. Q is the sister of R. S is the father of R. How is S related to P? (a) Brother (b) Father (c) Husband (d) Son
Q and R are siblings, so they share parents. P is their mother and S is their father, so S is P's husband. Answer: (c) Husband.

Q3. X is the child of Y. Y is the brother of Z. How is Z related to X? (a) Uncle (b) Aunt (c) Father (d) Cannot be determined
Y is X's parent and Z is Y's sibling, so Z is X's uncle or aunt. Z's gender is never given. Answer: (d) Cannot be determined.

Q4. Pointing to a man in a photograph, a woman says, "His mother is the only daughter of my father." How is the woman related to the man? (a) Sister (b) Mother (c) Aunt (d) Grandmother
The only daughter of the woman's father is the woman herself. So the man's mother is the woman. Answer: (b) Mother.

Q5. A # B means A is the father of B; A $ B means A is the sister of B; A @ B means A is the mother of B. What does P @ Q # R mean? (a) P is R's grandmother (b) P is R's mother (c) P is R's aunt (d) P is R's grandfather
P @ Q: P is Q's mother. Q # R: Q is R's father. P is two levels above R and is female. Answer: (a) P is R's grandmother (on the father's side).

Q6. M is the husband of N. N is the sister of O. O is the father of P. How is M related to P? (a) Uncle (b) Father (c) Brother-in-law (d) Grandfather
N is O's sister, so N is P's aunt (father's sister). M is N's husband, so M is P's uncle by marriage. Answer: (a) Uncle. Brother-in-law is what M is to O, not to P.

Coded relations: encoding

Some questions ask the reverse: "Which expression means M is the aunt of N?" Using the codes from Q5, M $ K # N says M is the sister of K and K is the father of N. M is female and is the sister of N's father, so M is N's aunt. Build the chain from the person asked about, one step at a time, and check that every gender the answer needs is fixed by the codes.

Generations

Count levels: grandparents +2, parents +1, your own level 0, children −1, grandchildren −2. Two levels apart on a direct line is a grandparent or grandchild. One level apart on a sibling's line is an uncle, aunt, nephew or niece. The same level on a sibling's child line is a cousin.

Practice

1. M is the father of N. N is the brother of O. How is O related to M? (a) Son (b) Daughter (c) Nephew (d) Cannot be determined
2. A is the sister of B. B is the son of C. C is the daughter of D. How is A related to D? (a) Daughter (b) Granddaughter (c) Niece (d) Sister
3. Pointing to a boy, a man says, "He is the son of my only brother." How is the boy related to the man? (a) Son (b) Brother (c) Nephew (d) Cousin
4. A + B means A is the son of B; A × B means A is the wife of B. What does P + Q × R mean? (a) P is R's son (b) P is R's brother (c) P is R's father (d) P is R's nephew
5. K is the husband of L. L is the mother of M. M is a girl. How is M related to K? (a) Niece (b) Daughter (c) Sister (d) Granddaughter
6. R is the brother of S. S is the wife of T. How is R related to T? (a) Brother (b) Cousin (c) Brother-in-law (d) Uncle
7. Pointing to a woman, a man says, "Her mother's only child is my wife." How is the woman related to the man? (a) Sister (b) Wife (c) Daughter (d) Sister-in-law
8. J is the grandson of K. K has only one child, L, who is a woman. How is J related to L? (a) Nephew (b) Brother (c) Son (d) Cousin

Answers:

1. (d) Cannot be determined. O is M's child, but O's gender is not given, so "son" and "daughter" are both possible.
2. (b) Granddaughter. A and B are C's children, C is D's daughter, and A is female ("sister").
3. (c) Nephew. The boy is the son of the man's brother.
4. (a) P is R's son. P is Q's son and Q is R's wife, so R is P's father.
5. (b) Daughter. M is L's child, K is L's husband, and M is a girl.
6. (c) Brother-in-law. R is the brother of T's wife.
7. (b) Wife. Her mother's only child is the woman herself, so she is the man's wife.
8. (c) Son. J is K's grandson, so J's parent is K's child. K's only child is L, so J is L's son.

What to do next

• Draw a tree for every blood relation question for the next two weeks, even the easy ones.
• Practise ten coded-relation questions both ways: decoding an expression and building one.
• Add every "cannot be determined" question you got wrong to your error log with the missing gender noted.
• Then move on to directions, where the same draw-as-you-read habit applies, and keep a mixed set going from the reasoning plan.