Given the following processes with their times and priority (lower number indicates higher priority)

Which of the following is a value of average waiting time using priority scheduling algorithm?

1. A9.2
2. B6.8
3. C7.6
4. D8.2

Pick an option to check yourself, or open the answer below.

Show answer & explanation

Correct answer: D. 8.2

Explanation

All arrive at 0. Order by priority: P2 (0–1), P5 (1–6), P1 (6–16), P3 (16–18), P4 (18–19). Waiting = 0 + 1 + 6 + 16 + 18 = 41; average 41/5 = 8.2.