Question 89359
let w equal the width of the path ... the dimensions of the remaining garden area are 30-2w long and 20-2w wide


(30-2w)(20-2w)=400 ... FOILing gives 600-100w+4w^2=400 ... dividing by 4 gives 150-25w+w^2=100 ... w^2-25w+50=0


quadratic formula gives {{{w=(25 +- sqrt(25^2-4*1*50))/(2*1)=(25 +- 5sqrt(17))/2}}}, so w=2.19 (approximately)