A massless rod $\mathrm{BD}$ of length $l$ is suspended by two identical massless strings $\mathrm{AB}$ and $\mathrm{CD }$of equal lengths. A block of mass $\mathrm{m}$ is suspended from a point $\mathrm{P}$ such that $\mathrm{BP}$ is equal to $\mathrm{x}$. If the fundamental frequency of the left wire is twice the fundamental frequency of the right wire, then the value of $\frac{l}{\mathrm{x}}$ is