Suppose that we have two tanks ( A and B ) between which a mixture of brine flows. Tank A contains 200 liters of water in which 20 kilograms of salt has been dissolved and Tank B contains 200 liters of water in which 10 kilograms of salt has been dissolved. Fresh water is pumped into Tank A at the rate of 200 liters per hour, and brine is pumped into Tank B from Tank A at the rate of 200 liters per hour. Brine is also drained at a rate 200 liters of brine per hour from Tank B . All brine mixtures are well-stirred. Find the amount of salt in each tank at time t .