A tank contains a mixture of water and salt, and at all times
the solution is kept will mixed. At time t = 0 there is 10 Liters
solution in the tank, with no salt. However, being poured into the
tank is a solution containing 2 grams of salt per liter, and it is
entering at a rate of 5 liters per minute. Simultaneously we drain
our tank at a rate of 3 liters per minute. Find the concentration
of...