Just a remark (or a correction) :
How are these differential equations ?I put this:
There is not even t in these expressions
This is how I see the problem.
Let's care about tank A first.
There are initially kg of X. So the ratio chemical/litre is
Hence if you remove a certain amount of litres, , there will be that will be removed.
Now, assuming that t is in minutes... We know that 5 litres are removed within 1 minutes.
So during t minutes, there are litres that are removed.
Can you see that if we consider the amount of chemical X removed during t, ?
So for tank A, there are kg of X that will be removed and go into tank B.
Similarly, there are kg of X that will be removed from tank B and that will go into tank A.
So your equations are :
(don't forget that there is initially a certain amount of chemical !)
do tell me if it looks incorrect to you