Let [tex]b=[/tex] Ben's age
Let [tex]d=[/tex] Daniel's age
We know:
[tex]b=d+20[/tex]
and
[tex]b-3=3(d-3)[/tex]
Plug the value of [tex]b[/tex] into the second equation:
[tex](d+20)-3=3(d-3)[/tex]
[tex]\rightarrow d+17=3d-9[/tex]
[tex]\rightarrow-2d+17=-9[/tex]
[tex]\rightarrow-2d=-26[/tex]
[tex]\rightarrow d=13[/tex]
Since Ben is 20 years older than Daniel, Ben is 13+20=33 years old.
