$8\mathrm{.}1$ Estimate the molar volume of a binary mixture containing $30$mol$\%$ propane $(1)$

and $70\%$ n$-$butane $(2)$ at $3$ bar and $450K.$ The mixture is represented by the

virial equation state.

$($Answer: $12,232c\frac{m^3}{m}ol)$

Allowed to use a solver like excel.