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