Show complete solution. Differential Equation. A 150-gal tank initially contains 80 lb of salt dissolved in 90 gal of water. Brine containing 2 lb/gal of salt flows into the tank at the rate of 5...

Show complete solution.

Differential Equation.


A 150-gal tank initially contains 80 lb of salt dissolved in 90 gal of water. Brine containing 2 lb/gal of salt flows into the tank at the rate of 5 gal/min, and the mixture flows out of the tank at the rate of 4 gal/min. If after 40 minures, how much salt does the tank contain?