One of your colleagues is developing the model for a blending tank that mixes a concentrated solution with water. The exit concentration is measured at a sampling station that is 100 ft away from the exit of the tank. An experiment is conducted by making a step change of 10 units in the concentration of the concentrated solution. The concentration of the exit stream increases from 50 to 55 g/liter. It takes 20 minutes to reach the new steady state in the exit concentration. A plant operator confirmed that the time constant for this system is 6 minutes. 1. Plot an approximate response of the exit concentration in this experiment. 2. Estimate the parameters of first-order-lag-plus-delay model for this system.