Question 1130566
d, the size of the uniform width surrounding the garden.


The description means that the total garden path plus garden is TWICE the area of the garden.  This is most likely the source of the "2" which you expect.


{{{(9+2d)(6+2d)=2*(9*6)}}}


Solve the equation for d.  Use whatever solution part makes sense.
Perimeter for the whole area will be  {{{2(9+2d)+2(6+2d).}}}