[Borek]

Tbh I dont care about the assumptions, I need the answer so I can work out how to do it.

Unfortunately for you, you can't have an answer without making an assumption. So logic here is - you don't care, you don't know the answer.

AWK already gave you half of the solution. The other one is that final volume is sum of volumes. This gives you set of equations that you have to solve.

[sjb]

Tbh I dont care about the assumptions, I need the answer so I can work out how to do it.

At the level you seem to be posing the question at, only one of the two sets of volumes add up to 200. That is assuming my addition skills are up to scratch, not sure if that's allowed under your ruling 

S

[mass]

whats the difference between the true parititon coefficient and the apparent parititon coefficient and which one is more important. I understand what the parititon coefficient is but need to learn these concepts.

[sjb]

http://www.boomer.org/c/p1/Ch22/Ch2203.html , perhaps?