Question 245670
Four years ago:
Anne = x
Katie = 2x
.
Today (four years later) 
Anne = x+4
Katie = 2x+4
.
In six years Anne will be the same age Katie is now.  So our equation becomes:
{{{x+4+6=2x+4}}}
Combine like terms and solve for x to find today's Anne's age.
I'll let you take it from here.  :)