Consider a data consisting of 10 observations $$x_1,x_2,\dots,x_{10}$$, whose mean is $$5$$ and variance is $$7$$. If the mean and the variance of the first 8 observations $$x_1,x_2,\dots,x_8$$ are $$4$$ and $$3.5$$, respectively, and $$x_9 < x_{10}$$, then the value of $$3x_9 + 2x_{10}$$ is ___________.