Hello to all, I want to analyze and make model of the water mixing process as shown in file in attacment. Basically, there are two input variables: input hot water flow and cold water flow. There is constant flow FL3. I need to write equation that describe how level and tank's temperature is changing. Equation for the level is: dh/dt=(FL1(t)+FL2(t)-FL3(t))/Area; And I need to figure out what equation to use to describe temperature. At first I thought that this is correct equation: V*dT/dt = Fl1*T1+Fl2*T2-(FL1+FL2)*T But I have saw different equation: V*dT/dt = Fl1*T1+Fl2*T2-FL3*T Which of these is correct? I know that these equations should be derived from heat equations m*C*(Ta-Tb), but not sure how to do this. Can you help?