Question 367018
{{{L=W+3}}}
The outer edges of the pit and flower bed are then,
{{{(L+2)}}} and {{{(W+2)}}}
or 
{{{(W+5)}}} and {{{(W+2)}}}
.
.
{{{(W+5)(W+2)=270}}}
{{{W^2+7W+10=270}}}
{{{W^2+7W-260=0}}}
{{{(W-13)(W+20)=0}}}
Two solutions but only the positive one makes sense.
{{{W-13=0}}}
{{{highlight(W=13)}}}ft
Then 
{{{L=13+3}}}
{{{highlight(L=16)}}}ft
The barbeque pit is 13 ft by 16 ft.