A) A tank initially contains 140 gal of brine in which 60 lb of salt are dissolved. A brine containing 2 lb/gal of salt runs into the tank at the rate of 9 gal/min. The mixture is kept uniform by stirring and flows out of the tank at the rate of 6 gal/min. Write, in standard form, the differential equation that models the mixing process. B) A tank initially contains 100 gal of brine in which 40 lb of salt are dissolved. A brine containing 2 lb/gal of salt runs into the tank at the rate of 4 gal/min. The mixture is kept uniform by stirring and flows out of the tank at the rate of 3 gal/min. Find the solution to the differential equation that models the mixing process. C)A tank initially contains 100 gal of brine in which 30 lb of salt are dissolved. A brine containing 1 lb/gal of salt runs into the tank at the rate of 6 gal/min. The mixture is kept uniform by stirring and flows out of the tank at the rate of 8 gal/min. Write, in standard form, the differential equation that models the mixing process. A tank initially contains 100 gal of brine in which 40 lb of salt are dissolved. A brine D) containing 2 lb/gal of salt runs into the tank at the rate of 4 gal/min. The mixture is kept uniform by stirring and flows out of the tank at the rate of 3 gal/min. Find the solution to the differential equation that models the mixing process.