How can I make VBA run through equations to solve for unknown values

[Same_Sabtos]

I have this project that I am working on and wondered if there was a way to make it easier/simpler. As for what I am trying to do, I am trying to have a set of values that essentially solve each other. Each value has multiple equations available to solve them and these values are used to solve for the other values using those equations. I want to make it so that I can input only 3 of any of those values to solve for the others. Any ideas on how to proceed with this problem?

 

[Same_Sabtos]

general idea but i dont think code-wise this works

 

[montecarlo2012]

Hi. Maybe somebody can give you help,
if you upload to the forum examples.
wich formula goes first and so on.
let me just assume I am able to help you
this forum expect something like:

Book1
	A	B	C	D
1		V
2		TOTAL	600
3		AIR	300
4		SOLID	200
5		WATER	100
6		VOID	50
7
8		AIR	300
9
10
Sheet1

so after this little miny tiny illustration then is possible to maybe help.
like:

Sub DiffEq()
air = Range("C3").Value
Solid = Range("C4").Value
water = Range("C5").Value
Total = Range("C2").Value

 Range("C8") = Total - Solid - water
 
End Sub

beautiful flow chart