A brine solution of salt flows at a constant rate of $6\frac{L}{m}in$ into a large tank that initially held $100L$ of pure water. The solution inside the tank is kept well stirred and flows out of the tank at a rate of $5\frac{L}{m}in.$ If the concentration of salt in the brine entering the tank is $0\mathrm{.}5k\frac{g}{L},$ determine the mass of salt in the tank after tmin. When will the concentration of salt in the tank reach $0\mathrm{.}3k\frac{g}{L}?$

Determine the mass of salt in the tank after $t$ min.

mass $=,kg$