$3\mathrm{.}3$ The table below shows jobs submitted for execution in a computer system with Time$-$sharing Capability.

$\backslash$table$[[$Process$,$Arriving Time$($ms$),$CPU Burst Time$($ms$)],[$P$1,0,5],[$P$2,2,10],[$P$3,4,12],[$P$4,6,2],[$P$5,8,3]]$

Using a$)$ First$-$Come$-$First$-$Served $($FCFS$)$ scheduling algorithm and b$)$ Shortest Job Next SJN $($Shortest Job First$)$ scheduling, calculate the average turnaround time for all the jobs $($Show calculations of the turnaround times for all processes$).$ Comment on your results on which scheduling algorithm is better. $(20$ Marks$)$