A 6-foot-high conical water tank is filled to the top. When a valve at the bottom of the tank is opened, the height h, in feet, of the water in the tank is given by h = (88.18 − 3.18t)2/5,
where t is the time in seconds after the valve is opened. Round answers to the nearest tenth.

Find the height of the water 18 s after the valve is opened.
ft

How long will it take to empty the tank?
seconds