A tank with a capacity of 1500 gals originally contains 1000 gals of fresh water. The first pipe containing 2 pounds of salt per gallon is entering at a rate of 4 gal/min. The second pipe containing 3 pounds of salt per gallon is entering at a rate of 6 gal/min. The mixture is allowed to flow out of the tank at a rate of 5 gal/min.
A. Find the amount of salt in the tank at any time PRIOR to the instant when the solution begins to overflow.