6 years ago, the average age of a family which includes father, mother and a son was 34 years. 3 years ago, the average age of father and mother was 45 years, what is the present age (in years) of the Son?

24

6 years ago total age of ( F + M + S ) = 34 × 3 = 102

At present total age of (F + M + S) = 102 + (6 × 3) = 120

3 years ago total age of ( F + M) = 45 × 2 = 90

At present total age of (F + M) = 90 + (3 × 2) = 96

Present age of Son = 120 - 96 = 24