If A + B means A is the brother of B; A - B means A is the sister of B and A x…

2026

If A + B means A is the brother of B; A - B means A is the sister of B and A x B means A is the father of B.

Which of the following means that C is the son of M?

  1. A.

    M - N x C + F

  2. B.

    F - C + N x M

  3. C.

    N + M - F x C

  4. D.

    M x N - C + F

Attempted by 1 students.

Show answer & explanation

Correct answer: D

In this coding scheme, '+' means 'is the brother of', '-' means 'is the sister of', and 'x' means 'is the father of'. To read a coded chain, decode each symbol left to right and link the relationships into one family tree, tracking each person's gender as it is revealed.

  1. M x N → M is the father of N.

  2. N - C → N is the sister of C, so N and C are siblings (children of the same parents, hence both children of M).

  3. C + F → C is the brother of F, which confirms C is male.

  4. Since M is the father of N and C is N's sibling, M is also the father of C; and since C is male, C is the son of M.

Checking the other coded chains:

  • M - N x C + F: M is the sister of N; N is the father of C — this makes M the paternal aunt of C, not a parent.

  • F - C + N x M: F is the sister of C; C is the brother of N; N is the father of M — this makes C the paternal uncle of M (the reverse relation), not a parent of C.

  • N + M - F x C: N is the brother of M; M is the sister of F; F is the father of C — this makes M the aunt of C, not the parent.

Only the chain 'M x N - C + F' establishes M as the father of a male child C, so it is the one that means C is the son of M.

Explore the full course: Tcs Live Preparation