Asingle water tank fills through two pipes. water flows through one pipe at a rate of 25,000 gallons an hour and through another pipe at a rate of 45,000 gallons an hour. water leaves the system at a rate of 60,000 gallons an hour. three of these water tanks hold a total of 870,000 gallons of water, and each tani is half full. if all the tanks are the same size, determine the number of hours it will take to fill all three tanks