Let the mean and the variance of \( 5 \) observations \( x_1, x_2, x_3, x_4, x_5 \) be \( \frac{24}{5} \) and \( \frac{194}{25} \) respectively. If the mean and variance of the first \( 4 \) observation are \( \frac{7}{2} \) and \( a \) respectively, then \( (4a + x_5) \) is equal to:
