Essential University Physics: Volume 1 (4th Edition)

We know that $3.0lb=(3.0)(0.454Kg)=1.362Kg$ $2100ft^2=(2100)(9.290\times 10^{-2}m^2)=195.09m^2$ Now $Coverage=\frac{195.09m^2}{1.362Kg}=143\frac{m^2}{Kg}$