Question 768297
Let age of the son be x
Since man is 3 times as old as son, man's age = 3x
Difference between their age = 20.
Thus,
3x - x = 20
2x = 20
x = 10
Thus age of son = 10
Age of the man = 3*10 = 30
Thus sum of their ages = 30 + 10 = 40