Question 67338
Let width(w)of rectangular garden be xft.
therefore length(l) of garden=2xft
a.l of garden and walk=(2x+2)ft
  w of garden and walk=(x+2)ft
  area of garden and walk=(2x+2)(x+2)=2x^2+2x+4x+4=(2x^2+6x+4)ft^2
b.area of only walk=area of garden and walk-area of garden 
  area of garden=(x)(2x)=2x^2ft^2
  area of only walk=(2x^2+6x+4)-2x^2=2x^2+6x+4-2x^2=(6x+4)ft^2
c.area of gravel=76ft^2
  area of only walk=76ft^2
  6x+4=76
  6x=72
  x=12ft
  l=2x=2*12=24ft
  w=x=12ft
  area of garden=24*12=288ft^2 
  therefore the garden should be of 288ft^2.