A tank contains 1000 L of pure water. Brine that contains 0.05 kg of salt per liter of water enters the tank at a rate of 5 L/mi
n. Brine that contains 0.04 kg of salt per liter of water enters the tank at a rate of 10 L/min. The solution is kept thoroughly mixed and drains from the tank at a rate of 15 L/min. (a) How much salt is in the tank after t minutes? y = kg
(b) How much salt is in the tank after 40 minutes? (Round the answer to one decimal place.) y(40) = kg