The Rate at Which Water Flows Out of a Drain

Multiple Choice

The rate at which water flows out of a drain in the bottom of a certain tank is proportional to the height of water in the tank. The tank is a vertical cylinder with cross-sectional area of 1.0 m², so that every 1 cm in height represents 10 L. If the flow is 10 L/min (i.e. 1 cm/min) when the water level is 700 cm, how long will it take for the level to go from 700 cm to 30 cm?

A) 4586 minutes
B) 670 minutes
C) 9 minutes
D) 2205 minutes