Model (not Solve) the system of differential equation if two connected tanks as tank-1 contains 1000 gal at water in which initially 200 kg at cement are dissolved and tank 2 contains i500 gal of water in which initially 300 kg of cement are dissolved. Fresh water runs in the tank-1 at the rate of 100gal/min. The mixture is pumped from each tank to the other at the rates that is 150gal/min from tank-1 to tank-2 and 50gal/min from tank-2 to tank-1. In addition, the mixture flows out from tank-2 at rate 100 gal/min.