You can put this solution on YOUR website! a father is 3 times as old as his son 3 years ago the sum of their ages was 50.How old is the son now
--------
Step 1 - find the sum of their ages now.
----
Also, some punctuation would be good.
a father is 3 times as old as his son. 3 years ago the sum of their ages was 50. How old is the son now