A Wheel of moment of inertia $0.10 \mathrm{kg}-{\mathrm{m}}^2$ is Rotating about a shaft at an angular speed of 160 rev/min A second wheel is set into rotation at 300 rev/min and is coupled to the same shaft so that both the wheels finally rotate with a common angular speed of 200 rev/min. The moment of inertia of the second wheel is /100 x ${\mathrm{kgm}}^2$, then ‘x’ is.