A step input tracer test (switching from tap water to salt water, measuring the conductivity of fluid

Question:

A step input tracer test (switching from tap water to salt water, measuring the conductivity of fluid leaving the vessel) is used to explore the flow pattern of fluid through the vessel (V = 1 m³, v = 1 m³/min). Devise a flow model to represent the vessel from the data of Figs. P12.7 to P12.10. C 0.3 (1-1) 0.3 30 40 1, sec