1. \(a \times b\) means a is the brother of b.
2. \(a+b\) means a is the father of b.
3. \(a-b\) means a is the sister of b.
Which of the following represents 'X is the uncle of M'?
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → \(X\times Y+M\)
Each symbol stands for one relation, read as “the left letter is the ... of the right letter”. The codes are:
\(a\times b\): a is the brother of b
\(a+b\): a is the father of b
\(a-b\): a is the sister of b
An uncle is the brother of a parent, so we need “X is the brother of Y” and “Y is the father of M”. Option (2), pair by pair:
\(X\times Y\): \(\times\) means brother, so X is the brother of Y (this pair also shows that X is male)
\(Y+M\): \(+\) means father, so Y is the father of M
X is the brother of M's father, so X is the uncle of M
Why the other options are incorrect
Option (1) \(X+Y-M\) — Incorrect. X is the father of Y, and Y is the sister of M, so X is M's father.
Option (3) \(X+Y\times M\) — Incorrect. X is the father of Y, and Y is the brother of M, so X is M's father.
Option (4) \(X-Y\times M\) — Incorrect. X is the sister of Y, and Y is the brother of M, so X is M's sister.