- #1
Monsterboy
- 303
- 96
Homework Statement
A tank contains 800 gal of water in which 200 lb of salt is dissolved. Two gallons of fresh water runs in per minute, and 2 gal of the mixture in the tank, kept uniform by stirring, runs out per minute. How much salt is left in the tank after 5 hours ?
Homework Equations
The Attempt at a Solution
[/B]
Let ##y## be the amount of salt present in the tank at any given time.
##y' \propto -y ##
##y' = -Cy ##
## \frac {dy}{dt} = -Cy ##
##\int \frac {1}{y} dy = -\int Cdt ##
## y = ke^{-Ct} ##
At ## t=0 , y_{0} = 200 = k##
## y = 200e^{-Ct} ##
I don't know how to find the value of ##C##.