blob84 0 Newbie Poster

Hi i'm reading the Silberschatz book about Operating system, 7th edition.
Theory is good but there is no support for exercises, nor exhaustive explanation.
I'm trying to do the exercise 5.4, calculate the average waiting time of round robin sheduling.

Process cpu-Burst priority
p1         10        3
p2          1        1
p3          2        3
p4          1        4
p5          5        2
quantum time is 1
arrival time is 0

How to calculate the average waiting time?