Solution

The correct answer is 8.2.

Key Points

• Priority Scheduling (Non-preemptive): Lower number ⇒ Higher priority.
• Processes with priorities: P₂(1), P₅(2), P₁(3), P₃(4), P₄(5).
• Execution Order: P₂ → P₅ → P₁ → P₃ → P₄.
• Gantt Chart (time in ms): P₂(0–1) → P₅(1–6) → P₁(6–16) → P₃(16–18) → P₄(18–19).
• 
• Waiting Times:
  • P₂ = 0
  • P₅ = 1
  • P₁ = 6
  • P₃ = 16
  • P₄ = 18
• Average Waiting Time: (0 + 1 + 6 + 16 + 18) / 5 = 41 / 5 = 8.2 ms.

Additional Information

• Important Points:
  • All processes arrive at time 0.
  • Non-preemptive scheduling executes a process completely once started.
  • Average waiting time = Σ Waiting Time / Number of processes.