Into a 1000-gal tank, initially filled with 100 gal of fresh water (density = 62.4 lb/ft), salt water containing 1.92 lb/gal of salt flows at a fixed rate of 4.0 gpm. the density of the incoming solution is 71.807 lb/ft? . the solution, kept uniform by stirring, flows out at a fixed rate of 19.2 lb/min. how many pounds of salt will there be in the tank at the end of 90 minutes? 1 ft = 7.48 gal.