Given, Condition (1) A@B = A is the mother of B. So R@S ⇒ R is the mother of S. R has only one child (given.) That is S. Condition (2) A!B = A is the granddaughter of B. So Q!R = Q is the granddaughter of R. So R, Q’s grandmother. So S became the mother of Q. Condition (3) A#B = A is the sister of B. So P#Q = P is the sister of Q. So S is the mother of P.