A 500-liter tank initially contains 10 g of salt dissolved in 200 liters of water. Starting at to = 0, water that contains 1/4 g of salt per liter is poured into the tank at the rate of 4 liters/min...

Extracted text: A 500-liter tank initially contains 10 g of salt dissolved in 200 liters of water. Starting at to = 0, water that contains 1/4 g of salt per liter is poured into the tank at the rate of 4 liters/min and the mixture is drained from the tank at the rate of 2 liters/min. Find an equation for the quantity m(t) of salt in the tank at time t prior to the time when the tank overflows and find the concentration C(t) (g/liter ) of salt in the tank at any such time.