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 * R + Q?
In a coded relation, if A ÷ B means A is the son of B, B + C means B is the sister of C, and C * D means C is the mother of D, what is the relationship of A to D?