A + B means A is the father of B ;
A - B means A is the wife of B ;
A x B means A is the brother of B ;
A ÷ B means A is the daughter of B.

If P x R - Q, which of the following is true ?

Answer: A. P is the brother-in-law of Q
P x R - Q means P is the brother of R who is the wife of Q i.e. P is the brother-in-law of Q.