A rectangular tank with a base area of 3600cm^2 and a height of 50cm contained some water. Tap X with water flowing out at a rate of 1.2 liter per minute was turned on at 0930 h to fill the tank. At 0945, Tap Y was turned on to drain water out of the tank at a rate of 1 litres per minute. If the tank started overflowing at 1130 h, find the volume of the water in the tank at first.(give your answer in litres)
