In a certain code language, 'A ? B' means ‘A is the mother of B’, 'A ! B' means ‘A is the wife of B’, 'A & B' means ‘A is the brother of B’ and 'A x B' means ‘A is the father of B’. Which of the following means that Z is the wife's father's mother of L?

Correct — A. Read the target backwards: Z is the mother of L's wife's father.

Rule: ? = mother of, ! = wife of, & = brother of, x = father of.

Option (a) reads Z ? B x T & J ! L:
Z ? B, so Z is the mother of B
B x T, so B is the father of T
T & J, so T is the brother of J, which makes B the father of J too

J ! L, so J is the wife of L.

Working back from L: his wife is J, J's father is B, and B's mother is Z. That is the wife's father's mother.

Why the others are wrong

• (b)
  Z ? B ! T & J x L — Z ? B ! T & J x L ends with J x L, meaning J is the father of L. The chain never reaches L through a wife, so the relationship the question asks for is never built.
• (c)
  Z ! B x T ? J & L — Z ! B x T ? J & L closes with J & L, meaning J is the brother of L. A brother cannot supply the wife the target needs, and Z here is a wife rather than a mother.
• (d)
  Z & B ! T x J ? L — Z & B ! T x J ? L opens with Z & B, meaning Z is the brother of B. That makes Z male, so Z cannot be anyone's mother.

Symbol blood-relation items hand you a private dictionary of operators and a target relationship written in ordinary English. The reliable method is to translate the target into a chain of steps first, then test each option symbol by symbol.

Here the target unpacks from L outwards: start at L, step to his wife, step to her father, step to that man's mother. The person you land on is Z.

Because the target is phrased in the opposite direction from the way an option is written, reading each option from its last symbol leftwards is usually faster than reading it forwards.

Key facts

• In this paper's code, ? is mother of, ! is wife of, & is brother of, and x is father of.
• In option (a) B is the father of J as well as of T, because T and J are brothers.
• All four operators fix the left-hand person's gender: ? and ! make that person female, x and & make that person male.

Common traps

• Reading an option left to right while the target is phrased right to left
• Missing that a brother link transfers the parent, so B fathers J as well as T
• Ignoring the gender an operator imposes, such as & making Z male in option (d)

No directly related past PYQ was found.