Physics · Rotational Motion

A solid disc and a thin ring are placed at rest, side by side, at the top of an inclined plane making an angle of 30° with the horizontal. They are released simultaneously and roll without slipping down the incline along the shortest path. If the difference in time taken by them to reach the bottom is 2 - √3√5 s, then the vertical height of the inclined plane (in metres) is ________. (Take g = 10 m/s2)