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Problem 2: The City of Regina is growing in population and the public works department projects the need for an increased water supply. The current water supply is drawn from a reservoir on a local stream and is of good quality, but future sources-the ones to be tapped next-have various problems. Water from a nearby aquifer is available in adequate supply, but its hardness level is too high unless it is blended with a lower hardness source. The total pounds of hardness per million gallons is limited to 1.200 (143 ppm in possibly more familiar terms) in the final blended supply. Water from a distant stream is of sufficient quality, but a pipeline would have to be built to convey it, and the cost to pump the water to the water treatment plant is quite high. The City of Regina is conducting its planning in stages. The first stage is to plan for ten years from the present. The three sources are: source 1- the current supply, source 2-the aquifer, and source 3- the distant stream. The costs to obtain water in dollars per million gallons, the supply limits in millions of gallons per day, and the hardness in pounds per million gallons are given below. For example, if the present water supply is developed further, up to 25 million gallons per day (mgd) could be made available from source 1 at a cost of $500 per million gallons. Each additional million gallons from this source would contribute 200 pounds of hardness to the total water supply. A total of 150 additional million gallons per day is needed by the end of ten years. Cost ($/mgd) Supply limit (mgd) Hardness (lb/mg) Source 1 500 25 200 Source 2 1000 120 2300 Source 3 2000 100 700 The city council members are interested in a least-cost strategy for expanding the water supply, while ensuring that the water supply remains of sufficient quality. Provide the optimal solution to the city council members