Mixing Problem
At t=0 in a tank is a solution with Volume V_0 and concentration c_0. There is a constant input of a solution with concentration c_i and a constant output.
You can see the the function A(t) which describes the amount of the substance in the tank at t and the function V(t) which gives the volume of the solution in the tank at t. You can change the parameters of the problem and the time t.
Check the different behaviour in the cases input<output, input=output and input>output.