A family consists of a father, a mother, and three children: X, Y, and Z. X is the eldest child and is a student. Y is a musician and Z is a painter. If the mother is a doctor, what can be inferred about the father's profession?
In a coded relationship, 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 daughter of Q, what is the relationship of R if P × R ÷ Q means P is the mother of R and R is the father of Q?