Five million gallons per day (MGD) of wastewater, with a concentration of 10.0 mg/L of a conservative pollutant, is released into a stream having an upstream flow of 10 MGD in a pollutant concentration of 3.0 mg/L. What is the concentration in ppm just downstream? (b) How many pounds of substance per day pass a given spot downstream? (The conversions 3.785 L/gal and 2.2 kg/lbm may be helpful.)

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