In a coded relation, if P ÷ Q means P is the mother of Q, P - Q means P is the father of Q, and P + Q means P is the sister of Q, what is the relationship of R if P ÷ Q - R?
If A × B means A is the sister of B, A + B means A is the brother of B, and A - B means A is the father of B, what is the relationship of C if A × C - B?