In the following arrangement, the system is initially at rest. The $5 \mathrm{kg}$block is now released. Assuming the pulleys and string to be massless and smooth. If the acceleration of block $\mathrm{C}$ is $\frac{x}{10} \mathrm{m} {\mathrm{s}}^{-2}$, then find the value of $x$. Take $\mathrm{g}=9.8\mathrm{ }\mathrm{m} {\mathrm{s}}^{-2}$.