Differential Equations mixing sugar and water

[hocuspocus102]

Homework Statement

A tank contains 2860 L of pure water. A solution that contains 0.04 kg of sugar per liter enters a tank at the rate 5 L/min The solution is mixed and drains from the tank at the same rate. Find the amount of sugar in the tank after t minutes.

Homework Equations

The Attempt at a Solution

Obviously it starts with 0 kg sugar and an initial condition at time t = 0.
The rate then would be equal to (the rate entering) - (the concentration exiting).
Entering = .04*5 = .2
Exiting = (Y*5)/2860 = Y/572

dY/dt = .2 - Y/527
dY/(.2 - Y/572) = dt
integrate both sides
-572ln(.2-Y/572) = t + C
simplify
ln(.2 - Y/572) = -t/572 + C
.2 - Y/572 = e^(-t/572+C)
-Y/572 = Ce^(-t/572) - .2
Y = Ce^(-t/572) + 114.4
initial value t = 0 and Y = 0
0 = Ce^(-0/572) + 114.4
C = -114.4
so Y = 114.4 - 114.4e^(-t/572)

Is this right because I've done it a bunch of times and keep getting the same answer, but it's an online problem and it tells me that it's wrong and I can't figure out what I did incorrectly. Thanks!

 

[Dick]

I don't see anything wrong with your solution. Beats me why the online thing won't take it.