$5$ moles of liquid benzene, $8$ moles of liquid toluene and $7$ moles of liquid xylene are mixed at $25^{\circ}C$ and $1$ bar. Assuming the formation of an ideal solution and using the universal gas constant $R = 8.314\: J\:\text{ mol}^{-1}\:K^{-1}$, the total entropy change is ___________________ $J\:K^{-1}$ (rounded off to one decimal place).