Problem: A storm sewer carries snow melt at the rate of 2000 L/min with a salt concentration of 5 g/L; it drains into a creek whose flow rate is 5000 L/min with a salt concentration of 1.2 mg/L just upstream of where the sewer joins it. What is the salt concentration downstream? Assume steady state; no chemical reactions (the salt is a "conservative substance"); and both the sewer and the creek are well mixed at the points of measurement. Begin with a schematic for the flow system with the data included in it.