A 50-gal tank initially contains 10 gal of fresh water. At t = 0, a brine solution containing 1lb of salt per gallon is poured into the tank at the rate of 4 gal/min, while the well-stirred mixture...

Extracted text: A 50-gal tank initially contains 10 gal of fresh water. At t = 0, a brine solution containing 1lb 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 (a) the amount of time required for overflow to occur and (b) the amount of salt in the tank at the moment of overflow.