Water is leaking out of an inverted conical tank at a rate of 6000 cm3/min at the same time that water is being pumped into the tank at a constant rate. The tank has height 7 m and the diameter at the top is 6 m. If the water level is rising at a rate of 18 cm/min when the height of the water is 2.5 m, find the rate at which water is being pumped into the tank.