a A storm sewer is mixed into a small stream. The stream before the mixing point has a NaCl concentration of 25 mg/L. If the storm sewer has a NaCl concentration of 1.8 g/L and the storm sewer flowrate is 2.5 L/min, calculate for the concentration of the salt in the stream after the discharge point (mixing point). The stream has a flowrate of 2.6 cu.m/s. Assume a complete mixing of the storm sewer flow and the stream flow. Assume also that the salt is nonreactive and that the system is at steady state