Water tank is in the shape of an inverted cone with depth 10 meters, and top radius 8 meters. Water is flowing into the tank at a rate of 0.1 cubic meters / min, but leaking out at a rate of 0.002h^20.002 h 2 cubic meters / min, where hh is the depth of water in the tank, in meters. Find the depth of water when the volume of water in the tank is neither increasing nor decreasing.