1. The problem statement, all variables and given/known data a) A large tank initially holds a mixture of 100 litres of water and 10 kg of salt. Fresh water is pumped in at a rate of 2L/min. The mixture is kept uniform by stirring and is pumped out at a rate of 2L/min. If x is the amount of salt present at any time t minutes, find the amount of salt present in the tank after 10 minutes. b) 0 = 1 - te^(-t/2) 2. Relevant equations 3. The attempt at a solution a. I would think this is a rate of change problem. I can imagine that the amount of salt will keep decreasing over time while the water volume stays at 100 litres. But I'm not able to form any equation to represent the problem. Can I get any help to solve this problem? b. I try to solve the equation but I don't have any luck. I think I need a numerical method to solve this equation. Can this equation be solved without using a numerical method? If numerical method the only way, which method should I use?