Four jobs to be executed on a single processor system arrive at time $${0^ + }$$ in the order $$A, B, C, D.$$ their burst $$CPU$$ time requirements are $$4, 1, 8, 1$$ time units respectively. The completion time of A under round robin scheduling with time slice of one time units.

The sequence $$.........$$ is an optimal non-preemptive scheduling sequence for the following jobs which leaves the $$CPU$$ idle for $$..........$$ Unit (s) of time

The details of an interrupt cycle are shown in Figure
Given that an interrupt input arrives every $$1$$ $$msec,$$ what is the percentage of the total time that the $$CPU$$ devotes for the main program execution.

Assume that the following jobs are to be executed on a single processor system.

Job Id	CPU Burst Time
p	4
q	1
r	8
s	1
t	2

The jobs are assumed to have arrived at time $${0^ + }$$ and in the order $$p,q,r,s,t.$$ Calculate the departure time (completion time) for job $$p$$ if scheduling is round robin with time slice$$1.$$