Identification of a ratio using Refractive indices (RESOLVED)

[Airp]

Homework Statement

I need to find the X of two substances using only the data found in lab. Which is: n_mixture=1.4156 n_butan-2-one=1.3787
n_toluene=1.4970 For the mixture, I don't know what X (the mole fraction) is. That is what I must find out.

Homework Equations

n_mixture= (X_butan-2-one *n_butan-2-one) + (X_Toluene *n_Toluene)

The Attempt at a Solution

What I did here is I said let x be equal to X for the butan-2-one and y be equal to X for the toluene...Then finding two equations to do a substitution...which obviously did not work...I also tried other things that basically ended up worse than this...I'm really stuck and I would need a lead! Thank you in advance for your help :) !

 

[Airp]

Oh, I actually found the solution... You have to add the X's which equal to one. With the system of equation you can substitute and only then you only have one unknown! (Is there a way to close the thread as it is not useful anymore :) )