Answer
$x_n=20(\sqrt[3]{2})$ft
Work Step by Step
As per the given problem, we have:
$H=k \dfrac{w}{x^3}$
Here, $k$ is defined as constant of proportionality
when the amount of wood gets doubled then we have
$k \dfrac{w}{x^3}=k \dfrac{w_n}{x_n^3}$
Plug the given data in the above expression, we get
$\dfrac{w}{(20)^3}=\dfrac{2w}{x_n^3}$
This gives: $x_n=20(\sqrt[3]{2})$ft
