Suppose we have a tank containing 1/2 lb of salt mixed in 1 gal of water. You pour salt into the tank at a rate of 2 lbs/min, and the well-stirred mixture leaves the tank at a rate in gal/min equal to the square of the current volume of water in the tank. How much salt is in the tank after 1 minute? Set up the initial value problem, and indicate what you are solving for.