Let the present age of the son be x.
Then, the present age of the father is 4x.
We know that when the son will be as old as his father is now, the sum of their ages will be 99. Let y be the number of years until this happens. Then, the son's age will be x+y and the father's age will be 4x+y.
According to the given condition:
x+y + (4x+y) = 99
Simplifying the above equation, we get:
5x + 2y = 99
We also know that y = 4x - x = 3x (since the father is currently three times as old as the son)
Substituting y = 3x in the above equation, we get:
5x + 2(3x) = 99
11x = 99
x = 9
Therefore, the present age of the son is x = 9 years and the present age of the father is 4x = 36 years.