A tank originally contains gal of fresh water. Then water containing lb of salt per gallon is poured into the tank at a rate of gal/min, and the mixture is allowed to leave at the same rate. After min the process is stopped, and fresh water is poured into the tank at a rate of gal/min, with the mixture again leaving at the same rate. Find the amount of salt in the tank at the end of an additional min. Round your answer to two decimal places.