Creatinine is a small molecule waste product that is found in urine and is an indicator of how well your kidneys are functioning. In the preeclampsia study above, the researchers want to extract creatinine from the urine samples using a solvent in a countercurrent staged extraction unit. The feed contains $10\frac{L}{m}in$ of creatinine at $7\frac{g}{L}$ in urine. The desired outlet concentration in the raffinate is to reduce the feed concentration by $90\%.$ The solvent is fed with a flow rate of $8\frac{L}{m}in.$ The equilibrium equation for this mixture is plotted on the next page.