jmc

The cylinder's original volume is $\pi r^{2}h$. The new height is $2h$ and the new radius is $r+\frac{200}{100}r=3r$. That means the new volume is $\pi (3r{)}^2(2h)=\pi r^{2}h(9)(2)$. The new volume is the original volume multiplied by a factor of $\boxed{18}$.