Step-by-step explanation The length of the square side = 5 m The height of the tank = 4 m The Volume of the square shaped tank is decreasing at a rate of 3 m3 per minute. The volume of the tank, V = lbh The volume of the tank when water level in the tank is at half its height (that is height = 2 m), V=5x5x2=50m3 V=Ah V=25h dV dh W25E @_i dt_25 (it &|% || 8|\" X A w V % _ 0.12m3/min Hence, the level of the water is decreasing at a rate of 0.12 m3 per min. Note: The water is drained at a constant rate hence the rate of decrease does not changes