Please help me with this question.

('3) Consider that there is a container having the shape of an inverted cone. It has a base- diameter of 120m and the height is twice as its diameter. The inverted cone contains the liquid and due to a small leakage at the bottom end, liquid flows out at the rate of 3m! of every second. Find the rate of change of the height of the liquid when the height of liquid is 16cm above its bottom end. (Express your answer in term of It)