A water tank has the shape of a rectangular prism of base 50 cm2

A water tank has the shape of a rectangular prism of base 50 cm2

A water tank has the shape of a rectangular prism of base 50 cm2. This tank is being filled at the rate of 12 liters per minutes. Find the rate at which the height of the water in the water tank increases; express your answer in millimeters per second.

Answer：40 mm/second