round robin scheduling

Question

Choose correct answer from the below options:
If the following jobs are to be executed on a single processor system

The jobs are arrived at time 0 and in the order a, b, c, d, e.
Calculate the departure time (completion time) for job ‘a’ if scheduling is round robin with time slice 1

1.   15
2.   5
3.   9
4.   11

Comments

I'm also getting 16

Answer 1

a	b	c	d	e	a	b	c	d	e	a	c	e	a	c	a	c
0-1	1-2	2-3	3-4	4-5	5-6	6-7	7-8	8-9	9-10	10-11	11-12	12-13	13-14	14-15	15-16	16-21

i think its 16