Mr. Santillana, a mathematics teacher, was traveling by bus with his family when the bus conductor questioned the age of his daughter to verify her half-fare ticket. Irritated, Mr. Santillana confused the conductor with his answer regarding her age. The problem can be solved by representing the present ages of Mr. Santillana, his mother, wife, son, and daughter with variables and equations relating their ages based on the information that the mother's age is the total of all their ages, which is now 69 years old. Solving the equation reveals that the daughter is 6 years old.