Suppose a brine containing $0\mathrm{.}2kg$ of salt per liter runs into a tank initially filled with $1250L$ of water containing $7kg$ of salt. The brine enters the tank at a rate of $5\frac{L}{m}in.$ The mixture, kept uniform by stirring, is flowing out at the rate of $5\frac{L}{m}in.$ Complete parts $($a$)$ and $($b$).$ rate of increase in $A=$ rate of input $-$ rate of exit.$]$

The concentration of salt in the tank after $10$ min will be $k\frac{g}{L}.$

$($Round to four decimal places as needed.$)$