The volume of the liquid in a spherical container of radius r is given in terms of the maximum depthh of the liquid by the formula V = n h2 (r- h); where in the formula, r is treated as a constant. If 4. 2m and the reservoir is drained at a constant rate of 3 l/s, how fast is the liquid level dropping when the depth is 300mm? [Note: 1l = 10 cm3 ] (7)