Atank contains 100 kg of salt and 2000 l of water. pure water enters a tank at the rate 12 l/min. the solution is mixed and drains from the tank at the rate 6 l/min. (a) what is the amount of salt in the tank initially? amount = (kg) (b) find the amount of salt in the tank after 1.5 hours. amount = (kg) (c) find the concentration of salt in the solution in the tank as time approaches infinity. (assume your tank is large enough to hold all the solution.) concentration = (kg/l)