Answer: Let's call the present age of the son x and the present age of the father y.
We know that y = 3x and that six years ago, the sum of their ages was 45.
So, we can write the equation:
x + (y-6) = 45
x + (3x-6) = 45
4x = 51
x = 12.75
The present age of the son is 12.75 years.
Explanation: