A water tank has the shape of an inverted right circular cone, whose semi-vertical angle is $\tan^{-1}\left(\dfrac{1}{2}\right)$. Water is poured into it at a constant rate of $5$ cubic meter per minute. The rate (in m/min) at which the level of water is rising at the instant when the depth of water in the tank is $10\text{ m}$, is: