A large tank is filled to capacity with 400 gallons of pure water. Brine containing 2 pounds of salt per gallon is pumped into the tank at a rate of 4 gal/min. The well-mixed solution is pumped out at the same rate. Find the number A(t) of pounds of salt in the tank at time t. [Note: This question is expecting that you input the right hand side of the explicit solution A(t) to the initial value problem. ] A(t)