Both the strings, shown in the figure are made of the same material and have the same cross-section. The pulleys are light. The wave speed of a transverse wave in the string $\mathrm{A}\mathrm{B}$ is ${\mathrm{v}}_1$ and in the $\mathrm{C}\mathrm{D}$ it is ${\mathrm{v}}_2$. Then $\frac{{\mathrm{v}}_1}{{\mathrm{v}}_2}$ is