Question 84427
the length of the remaining garden area is the original length minus twice the width of the path, similarly with the original width  ... let x=width of path


(30-2x)(20-2x)=400 ... 600-100x+4x^2=400 ... x^2-25x+50=0 ... {{{x=(25 +- sqrt(25^2-4*1*50))/(2*1)}}} ... {{{x=(25 +- sqrt(425))/2}}}


x=12.5 +- 2.5(sqrt(17)) ... x approximately equals 22.81 and 2.19


the 22.81 is not realistic based on the garden size