1. The problem statement, all variables and given/known data Suppose that a large mixing tank initially holds 400 gallons of water in which 65 pounds of salt have been dissolved. Another brine solution is pumped into the tank at a rate of 6 gal/min, and when the solution is well stirred, it is pumped out at a faster rate of 8 gal/min. If the concentration of the solution entering is 3 lb/gal, determine a differential equation for the amount A(s) of salt in the tank at time t. 2. Relevant equations Flow rate is Volume times cross sectional area, however, I do not know if that is relevant, it has been a while since I have done something like this.