|Que.||An operating system uses shortest remaining time first scheduling algorithm for pre-emptive scheduling of processes. Consider the following set of processes with their arrival times and CPU burst times (in milliseconds):
Process : Arrival Time Burst Time
P1 : 0 12
P2 : 2 4
P3 : 3 6
P4 : 8 5
The average waiting time (in milliseconds) of the processes is _________.