$3.(10$ points$)$ Consider a fish tank that initially contains $200$ liters of water with $50$ grams of salt $($pollutant$)$ dissolved in it$.$ The salt concentration in the tank needs to be decreased from the $0\mathrm{.}25$ grams per liter to $0\mathrm{.}1$ grams per liter to accommodate a new species of fish. Tap water $($containing $0\mathrm{.}04$ grams of salt per liter$)$ is allowed to run into the tank at a rate of $1\mathrm{.}5$ liters per minute. The thoroughly stirred mixture in the tank is allowed to drain out of the tank at the same rate $(1\mathrm{.}5$ liters per minute$).$ Construct a well$-$labeled diagram of this scenario AND create a differential equation $($specifically an initial value problem$)$ that models this scenario. You do NOT need to solve the differential equation!