Five batch jobs A through E$,$ arrive at a computer center

at almost the same time. They have estimated running

times of $7,6,3,5,$ and $9$ minutes. Their $($externally

determined$)$ priorities are $3,2,1,5,$ and $4,$ respectively,

with $5$ being the highest priority. For each of the following

scheduling algorithms, determine the mean process turn$-$

around time. Ignore process switching overhead.

$($a$)$ Round robin $($with time slice of $2$ minute$).$

$($b$)$ Priority scheduling.

$($c$)$ First$-$come, first served $($run in order A$,$ B$,$ C$,$ D$,$ E$)$

$($d$)$ Shortest job first.

$5$