A 50 gallon tank initially contains 10 gallons of fresh water. At t=0\displaystyle {t}={0} a brine solution containing 1 pound of salt per gallon is poured into the tank at the rate of 4 gal/min., while the well-stirred mixture leaves the tank at the rate of 2 gal/min. Find the amount of salt in the tank at the moment of overflow.

Enter answer as numerical decimal correct to two decimal places. pounds.