# Numerical Solved by Round Robin

Q2. Take four processes that arrive at the same time in the following order and the time quantum is 20.

Process                         Burst Time

P1                                    53

P2                                    17

P3                                    68

P4                                    24

Draw Gantt Chart and calculate average turnaround and waiting time using Round Robin Scheduling Algorithm.

Ans.

Gantt Chart:

 P1 P2 P3 P4 P1 P3 P4 P1 P3 P3

0           20           37          57          77           97         117        121         134         154     162

Waiting Time

P1’s waiting time=57+24=81

P2’s waiting time=20

P3’s waiting time=37+40+17=94

P4’s waiting time=57+40=97

Average Waiting Time

=(81+20+94+97)/4

=73 milliseconds

Turnaround Time

Turnaround Time = Burst Time + Waiting Time

P1=53+81=134

P2=17+20=37

P3=68+9=162

P4=24+97=121

Average Turnaround Time

=(134+37+162+121)/4

=113.5 millisecond

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