If A + B means A is the brother of B, A - B means A is the sister of B, and A × B means A is the father of B, what is the relationship of C if A + C - B means A is the brother of C and C is the sister of B?
If X ÷ Y means X is the mother of Y, X * Y means X is the father of Y, and X - Y means X is the sister of Y, what is the relationship of Z if X ÷ Z * Y means X is the mother of Z and Z is the father of Y?
If P + Q means P is the sister of Q, P - R means P is the mother of R, and R × S means R is the son of S, what is the relationship of Q to S if P + Q - R × S means P is the sister of Q, P is the mother of R, and R is the son of S?