Please comment your solutions, questions and remarks..
This is quite famous. But maybe you haven’t heard it yet:
A math student goes to a party organized by her supervisor. The student asks: How many daughters do you have? And the supervisor answers: three. The student asks about their ages and the supervisor replies: “If you multiply their ages, you get 36 and if you sum the ages, you get the number of our house.” The student thought for a while and said “There is something you didn’t tell” and the supervisor replied “Oh yeah, the oldest one plays piano.” Then the student immidiately realizes the ages.