Question 737416
Let m=man's age
Then s =son's age = m-32

Man's age ten years ago was m-10
Son's age ten years ago was m - 32 -10=m-42
But we also know man 10 years ago = 3*  son 10 years ago 

So {{{m-10=3*(m-42)}}}
Distribute and simplify:
M
{{{m-10=3m-3(42)=3m-126}}}

{{{m-10=3m-126}}}
Subtract m from both sides
{{{-10=2m-126}}}
Add 126 to both sides
{{{116=2m}}} and divide by 2 on both sides to get m =58.

So the man is now 58 years old. Going to the top, we find his son is 32  years younger, so his son is 58-32=26.

To check, go back ten years: the man was 48 and his son was 16 and 48=3*16.