A reservoir is designed to provide hydroelectric power and water for irrigation. The outflow from the reservoir is used to generate hydroelectric power and after passing through the turbines it can be diverted toward an irrigation project or it can continue to flow downstream. At least one unit of water must be left to flow down the stream each month. The reservoir has a capacity of 10 units of water. It currently contains 5 units of water and must contain 5 units of water at the end of the year. The maximum amount that can be released in any month is 7 units. The return (profit) for each unit of water released for hydroelectric power and irrigation and the estimated inflow for each month of a year are shown in the following table. Formulate the linear programming model that would be solved to determine how much water to release each month of the year so that the returns from hydroelectric power and irrigation will be maximized.