Let the mean and the variance of 5 observations x_1, x_2, x_3, x_4, x_5 be 24/5 and 194/25 respectively. If the mean and variance of the first 4…

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