a cylindrical tank is used to store water for a town. on any given day, the water supply inflow per day may fill the tank with additional 6, 7, or 8ft of water. the daily demand or consumption of the water for the town will draw down the water level in the tank by an amount equivalent to 5, 6, or 7ft of the water in the tank. what are the possible combinations of inflow and outflow of water in the tank in a given day? if the water level in the tank is 7ft from the bottom at the start of day, what are the possible water levels in the tank at the end of the day?