A mixing tank initially holds 1 0 0 L of a brine solution with a salt concentration of 0 . 0 5 kg / L
A mixing tank initially holds Lof a brine solution with a salt concentration of kgL For the first minutes a valve A is open adding Lmin of brine containing kgL salt concentration. When minutes passed, valve A shuts off and another valve B opens to release Lmin of brine with a concentration of salt of kgL The well mixed solution in the tank flows out at the same rate of Lmin Letyt denote the amount of salt in the tank at time t
