A, B, C, D, E and F are six members of a family. B is married to C. F is the mother of E and D is the daughter of F. A’s daughter is E and C’s son is A. There are two married couples in the family. Which of the following is correct ?

Correct — option (4), E is granddaughter of C.

Work through the clues, noting what each one fixes.
"C's son is A": A is male and is C's child.
"B is married to C": B, as C's spouse, is A's other parent.
"A's daughter is E": E is female and is A's child.

"F is the mother of E": F is female, so A and F are E's parents.
"There are two married couples": B and C, and A and F.
"D is the daughter of F": D is female.

Now test option (4). E is a daughter of A, and A is a son of C, so E is C's granddaughter. Beyond that chain, the word "granddaughter" needs only E's gender, which the stem gives. So E is granddaughter of C is certain.

The stem does not give the gender of B or C, and options (1), (2) and (3) each depend on it. If B were taken as male and C as female, options (1) and (2) would be true, and so would (3) on reading D as A's daughter too; the stem settles none of this.

The idea to remember: a relation word fixes the gender of the person it describes, so check whether the stem actually gives that gender.

Why the others are wrong

• (1)
  B is grandfather of E. — B, as C's spouse and A's parent, is a grandparent of E. But "grandfather" also says B is male, and the stem does not give B's gender.

  "B is married to C" names a couple without saying which is the husband. So option (1) may be true, but it cannot be confirmed from the clues.

• (2)
  C is mother of A. — C is A's parent — "C's son is A" says so. But "mother" also says C is female, and the stem does not give C's gender.

  The clue fixes A's gender (son), not C's. So option (2) cannot be confirmed; C could equally be A's father on the clues given.

• (3)
  C is grandmother of D. — "Grandmother" says C is female, and the stem does not give C's gender.

  The link between C and D also rests on reading D, F's daughter, as A's daughter too. Even granting that, C could be D's grandfather on the clues given, so option (3) cannot be confirmed.

In a relations puzzle, draw the family as a tree: each generation on its own level, marriages joined sideways, children below their parents. Mark a gender only when the clues give it.

A relation word fixes the gender of the person it describes. "A is C's son" makes A male; it says nothing about C. "B is married to C" joins a couple but does not say which one is the husband.

An option is correct only if it holds under every arrangement the clues allow. If it depends on a gender the stem leaves open, it cannot be confirmed.

Key facts

• A relation word fixes the gender of the person it describes: "C's son is A" makes A male and says nothing about C.
• "B is married to C" names a couple without saying which of them is the husband.
• In this family, B and C are A's parents, and A and F are E's parents; D is F's daughter.
• Genders given by the stem: A male; D, E and F female; B and C not stated.
• E, a daughter of C's son A, is C's granddaughter whatever C's gender.

Common traps

• "B is married to C" names a couple, not a husband and a wife. Do not assign genders the stem does not give.
• A relation word describes the gender of its subject only. "E is granddaughter of C" needs E to be female, which the stem states; it says nothing about C.
• When several options become true together under one unstated assumption, look for the option that needs no assumption.

UnlockIAS will link similar questions from RAS Pre 2023 and 2016 here once those papers are published on this site.

• practice — not a real PYQ

  P, Q, R, S and T are members of a family. R is married to P. Q is the son of P. S and T are the daughter and son of Q. Which of the following is definitely true?

  • (a)R is the grandmother of S.
  • (b)P is the grandfather of T.
  • (c)T is the grandson of P.
  • (d)R is the mother of Q.
  Answer(3) — T is a son of Q, and Q is a son of P, so T is P's grandson; beyond that chain it needs only T's gender, which is given. Options (1) and (4) need R to be female, and option (2) needs P to be male, but the clues give neither gender.
• practice — not a real PYQ

  Pointing to a man, Kavita said, "His mother is the only daughter of my mother." How is Kavita related to the man?

  • (a)Sister
  • (b)Mother
  • (c)Aunt
  • (d)Grandmother
  Answer(2) — Kavita is a daughter of her mother, so "the only daughter of my mother" is Kavita herself. The man's mother is therefore Kavita. Option (1) would put them in the same generation; option (3) would make his mother Kavita's sister, but Kavita's mother has only one daughter; option (4) is two generations up.