A hanging mass M is connected to a four times bigger mass by using a string-pulley arrangement, as shown in the figure. The bigger mass is placed on…

A hanging mass M is connected to a four times bigger mass by using a string-pulley arrangement, as shown in the figure. The bigger mass is placed on a horizontal ice-slab and being pulled by $\displaystyle 2$ Mg force. In this situation, tension in the string is $\displaystyle \frac{\mathrm{x}}{5} \mathrm{Mg}$ for $\displaystyle \mathrm{x}=$ \_\_\_\_. Neglect mass of the string and friction of the block (bigger mass) with ice slab. (Given $\displaystyle \mathrm{g}=$ acceleration due to gravity)