Total age of x and y is 15 years more than the sum of the ages of y and z. What is the value of (x - z) ?

The sum of the present ages of a man and his son is 50 years. After five years, the man's age will be three times that of his son. Find the present age of the son.

The sum of the present ages of a father and his son is 75 years. Fifteen years ago, father's age was eight times the age of the son. After 7 years, son's age will be

The sum of the ages of a father and his son is 50 years. Five years ago, the father's age was 4 times his son's age. Find their present ages.

The total age of father and son at present is 40 years. 16 years since hence the age of father will be twice the age of his son. What is the age of son at present ?

The age of a man is 4 times that of his son. Five years ago, the man was 7 times as old as his son at that time. What is the present age of the man?

If 5 times a son's age is added to his father's age, the sum is 42 years. If 2.8 times the father's age is added to the son's age, the sum is 76 years. What is the father's age (in years)?

The average age of 28 students of a class is 40 years. If the age of the teacher is also included, the average age of the whole group becomes 41 years. The age (in years) of the teacher is:

The sum of the ages of three friends is 188 years. What was the sum of their ages 10 years ago?

Six times the present age of P exceeds the present age of Q by 46 years. After 10 years, six times Q’s age will be 18 years less than five times P’s age at that time. What is the present age of Q (in years)?​

Three times the present age of P exceeds the present age of Q by 23 years. After 7 years, six times Q’s age will be 30 years less than six times P’s age at that time. What is the present age (in years) of Q?