The mass per unit length of a non-uniform rod of length L varies as $\mathrm{m}={\mathrm{m}}_0 \frac{{\mathrm{X}}^2}{\mathrm{L}}$, where ${\mathrm{m}}_0$ is a constant and X is the distance of any point on the rod measured from one end. The centre of mass of the rod is at $\frac{\mathrm{PL}}{4}$ where P is