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Machine Breakdown Recovery - Intermediate Level: tricky scenarios handling Machine Breakdown Recovery INTERMEDIATE

This expert challenge 📈 worksheet focuses on Machine Breakdown Recovery - a key topic in Scheduling. You'll solve 20 intermediate-level problems (Worksheet 5 of 10). The primary focus is on tricky scenarios handling. Master how to solve machine breakdown recovery, machine breakdown recovery tricks, and machine breakdown recovery shortcut methods through systematic practice.

📝 Worksheet 5 of 10 • 20 questions • ⏱️ Estimated time: 20 minutes • 🎯 Intermediate level

What you'll learn in this worksheet:
Your progress through Machine Breakdown Recovery
Worksheet 5 of 10 (44% complete)

Question 1

A machine needs to process 4 jobs. Processing times: - Job C: 90 minutes - Job E: 85 minutes - Job A: 78 minutes - Job B: 74 minutes The machine breaks down at 75 minutes and takes 40 minutes to repair. Jobs are scheduled using Shortest Processing Time (SPT) first rule. What is the total completion time (makespan) after handling the breakdown?
Step-by-step solution (Breakdown Recovery):

1. Original SPT order: Job B → Job A → Job E → Job C
2. Simulate processing with breakdown:
- Job B: 0 → 74
- Job A: Starts at 74, breakdown at 75 (1 min completed), repair 40 min, resume 77 min → completes at 192
- Job E: 192 → 277
- Job C: 277 → 367

3. Total makespan: 367 minutes
4. Delay caused by breakdown: 40 minutes

Answer: 367 minutes

Key Strategy: Simulate the timeline, account for breakdown during active job processing.

Question 2

A machine needs to process 4 jobs. Processing times: - Job B: 35 minutes - Job D: 67 minutes - Job C: 68 minutes - Job E: 70 minutes The machine breaks down at 90 minutes and takes 27 minutes to repair. Jobs are scheduled using Shortest Processing Time (SPT) first rule. What is the total completion time (makespan) after handling the breakdown?
Step-by-step solution (Breakdown Recovery):

1. Original SPT order: Job B → Job D → Job C → Job E
2. Simulate processing with breakdown:
- Job B: 0 → 35
- Job D: Starts at 35, breakdown at 90 (55 min completed), repair 27 min, resume 12 min → completes at 129
- Job C: 129 → 197
- Job E: 197 → 267

3. Total makespan: 267 minutes
4. Delay caused by breakdown: 27 minutes

Answer: 267 minutes

Key Strategy: Simulate the timeline, account for breakdown during active job processing.

Question 3

A machine needs to process 4 jobs. Processing times: - Job E: 46 minutes - Job C: 90 minutes - Job D: 76 minutes - Job B: 84 minutes The machine breaks down at 81 minutes and takes 34 minutes to repair. Jobs are scheduled using Shortest Processing Time (SPT) first rule. What is the total completion time (makespan) after handling the breakdown?
Step-by-step solution (Breakdown Recovery):

1. Original SPT order: Job E → Job D → Job B → Job C
2. Simulate processing with breakdown:
- Job E: 0 → 46
- Job D: Starts at 46, breakdown at 81 (35 min completed), repair 34 min, resume 41 min → completes at 156
- Job B: 156 → 240
- Job C: 240 → 330

3. Total makespan: 330 minutes
4. Delay caused by breakdown: 34 minutes

Answer: 330 minutes

Key Strategy: Simulate the timeline, account for breakdown during active job processing.

Question 4

A machine needs to process 4 jobs. Processing times: - Job C: 46 minutes - Job D: 90 minutes - Job A: 66 minutes - Job E: 32 minutes The machine breaks down at 70 minutes and takes 31 minutes to repair. Jobs are scheduled using Shortest Processing Time (SPT) first rule. What is the total completion time (makespan) after handling the breakdown?
Step-by-step solution (Breakdown Recovery):

1. Original SPT order: Job E → Job C → Job A → Job D
2. Simulate processing with breakdown:
- Job E: 0 → 32
- Job C: Starts at 32, breakdown at 70 (38 min completed), repair 31 min, resume 8 min → completes at 109
- Job A: 109 → 175
- Job D: 175 → 265

3. Total makespan: 265 minutes
4. Delay caused by breakdown: 31 minutes

Answer: 265 minutes

Key Strategy: Simulate the timeline, account for breakdown during active job processing.

Question 5

A machine needs to process 4 jobs. Processing times: - Job E: 62 minutes - Job A: 55 minutes - Job D: 85 minutes - Job B: 43 minutes The machine breaks down at 66 minutes and takes 23 minutes to repair. Jobs are scheduled using Shortest Processing Time (SPT) first rule. What is the total completion time (makespan) after handling the breakdown?
Step-by-step solution (Breakdown Recovery):

1. Original SPT order: Job B → Job A → Job E → Job D
2. Simulate processing with breakdown:
- Job B: 0 → 43
- Job A: Starts at 43, breakdown at 66 (23 min completed), repair 23 min, resume 32 min → completes at 121
- Job E: 121 → 183
- Job D: 183 → 268

3. Total makespan: 268 minutes
4. Delay caused by breakdown: 23 minutes

Answer: 268 minutes

Key Strategy: Simulate the timeline, account for breakdown during active job processing.

Question 6

A machine needs to process 4 jobs. Processing times: - Job B: 73 minutes - Job A: 50 minutes - Job E: 63 minutes - Job D: 44 minutes The machine breaks down at 96 minutes and takes 15 minutes to repair. Jobs are scheduled using Shortest Processing Time (SPT) first rule. What is the total completion time (makespan) after handling the breakdown?
Step-by-step solution (Breakdown Recovery):

1. Original SPT order: Job D → Job A → Job E → Job B
2. Simulate processing with breakdown:
- Job D: 0 → 44
- Job A: 44 → 94
- Job E: Starts at 94, breakdown at 96 (2 min completed), repair 15 min, resume 61 min → completes at 172
- Job B: 172 → 245

3. Total makespan: 245 minutes
4. Delay caused by breakdown: 15 minutes

Answer: 245 minutes

Key Strategy: Simulate the timeline, account for breakdown during active job processing.

Question 7

A machine needs to process 4 jobs. Processing times: - Job E: 71 minutes - Job A: 87 minutes - Job C: 85 minutes - Job B: 81 minutes The machine breaks down at 109 minutes and takes 38 minutes to repair. Jobs are scheduled using Shortest Processing Time (SPT) first rule. What is the total completion time (makespan) after handling the breakdown?
Step-by-step solution (Breakdown Recovery):

1. Original SPT order: Job E → Job B → Job C → Job A
2. Simulate processing with breakdown:
- Job E: 0 → 71
- Job B: Starts at 71, breakdown at 109 (38 min completed), repair 38 min, resume 43 min → completes at 190
- Job C: 190 → 275
- Job A: 275 → 362

3. Total makespan: 362 minutes
4. Delay caused by breakdown: 38 minutes

Answer: 362 minutes

Key Strategy: Simulate the timeline, account for breakdown during active job processing.

Question 8

A machine needs to process 4 jobs. Processing times: - Job E: 44 minutes - Job A: 56 minutes - Job B: 38 minutes - Job C: 58 minutes The machine breaks down at 115 minutes and takes 34 minutes to repair. Jobs are scheduled using Shortest Processing Time (SPT) first rule. What is the total completion time (makespan) after handling the breakdown?
Step-by-step solution (Breakdown Recovery):

1. Original SPT order: Job B → Job E → Job A → Job C
2. Simulate processing with breakdown:
- Job B: 0 → 38
- Job E: 38 → 82
- Job A: Starts at 82, breakdown at 115 (33 min completed), repair 34 min, resume 23 min → completes at 172
- Job C: 172 → 230

3. Total makespan: 230 minutes
4. Delay caused by breakdown: 34 minutes

Answer: 230 minutes

Key Strategy: Simulate the timeline, account for breakdown during active job processing.

Question 9

A machine needs to process 4 jobs. Processing times: - Job C: 35 minutes - Job D: 46 minutes - Job A: 81 minutes - Job E: 34 minutes The machine breaks down at 81 minutes and takes 41 minutes to repair. Jobs are scheduled using Shortest Processing Time (SPT) first rule. What is the total completion time (makespan) after handling the breakdown?
Step-by-step solution (Breakdown Recovery):

1. Original SPT order: Job E → Job C → Job D → Job A
2. Simulate processing with breakdown:
- Job E: 0 → 34
- Job C: 34 → 69
- Job D: Starts at 69, breakdown at 81 (12 min completed), repair 41 min, resume 34 min → completes at 156
- Job A: 156 → 237

3. Total makespan: 237 minutes
4. Delay caused by breakdown: 41 minutes

Answer: 237 minutes

Key Strategy: Simulate the timeline, account for breakdown during active job processing.

Question 10

A machine needs to process 4 jobs. Processing times: - Job D: 77 minutes - Job E: 80 minutes - Job C: 54 minutes - Job A: 85 minutes The machine breaks down at 98 minutes and takes 36 minutes to repair. Jobs are scheduled using Shortest Processing Time (SPT) first rule. What is the total completion time (makespan) after handling the breakdown?
Step-by-step solution (Breakdown Recovery):

1. Original SPT order: Job C → Job D → Job E → Job A
2. Simulate processing with breakdown:
- Job C: 0 → 54
- Job D: Starts at 54, breakdown at 98 (44 min completed), repair 36 min, resume 33 min → completes at 167
- Job E: 167 → 247
- Job A: 247 → 332

3. Total makespan: 332 minutes
4. Delay caused by breakdown: 36 minutes

Answer: 332 minutes

Key Strategy: Simulate the timeline, account for breakdown during active job processing.

Question 11

A machine needs to process 4 jobs. Processing times: - Job C: 38 minutes - Job B: 68 minutes - Job E: 79 minutes - Job A: 59 minutes The machine breaks down at 86 minutes and takes 40 minutes to repair. Jobs are scheduled using Shortest Processing Time (SPT) first rule. What is the total completion time (makespan) after handling the breakdown?
Step-by-step solution (Breakdown Recovery):

1. Original SPT order: Job C → Job A → Job B → Job E
2. Simulate processing with breakdown:
- Job C: 0 → 38
- Job A: Starts at 38, breakdown at 86 (48 min completed), repair 40 min, resume 11 min → completes at 137
- Job B: 137 → 205
- Job E: 205 → 284

3. Total makespan: 284 minutes
4. Delay caused by breakdown: 40 minutes

Answer: 284 minutes

Key Strategy: Simulate the timeline, account for breakdown during active job processing.

Question 12

A machine needs to process 4 jobs. Processing times: - Job C: 85 minutes - Job B: 76 minutes - Job A: 58 minutes - Job E: 89 minutes The machine breaks down at 63 minutes and takes 34 minutes to repair. Jobs are scheduled using Shortest Processing Time (SPT) first rule. What is the total completion time (makespan) after handling the breakdown?
Step-by-step solution (Breakdown Recovery):

1. Original SPT order: Job A → Job B → Job C → Job E
2. Simulate processing with breakdown:
- Job A: 0 → 58
- Job B: Starts at 58, breakdown at 63 (5 min completed), repair 34 min, resume 71 min → completes at 168
- Job C: 168 → 253
- Job E: 253 → 342

3. Total makespan: 342 minutes
4. Delay caused by breakdown: 34 minutes

Answer: 342 minutes

Key Strategy: Simulate the timeline, account for breakdown during active job processing.

Question 13

A machine needs to process 4 jobs. Processing times: - Job D: 46 minutes - Job C: 65 minutes - Job E: 68 minutes - Job B: 41 minutes The machine breaks down at 87 minutes and takes 44 minutes to repair. Jobs are scheduled using Shortest Processing Time (SPT) first rule. What is the total completion time (makespan) after handling the breakdown?
Step-by-step solution (Breakdown Recovery):

1. Original SPT order: Job B → Job D → Job C → Job E
2. Simulate processing with breakdown:
- Job B: 0 → 41
- Job D: 41 → 87
- Job C: Starts at 87, breakdown at 87 (0 min completed), repair 44 min, resume 65 min → completes at 196
- Job E: 196 → 264

3. Total makespan: 264 minutes
4. Delay caused by breakdown: 44 minutes

Answer: 264 minutes

Key Strategy: Simulate the timeline, account for breakdown during active job processing.

Question 14

A machine needs to process 4 jobs. Processing times: - Job A: 30 minutes - Job E: 62 minutes - Job D: 63 minutes - Job B: 57 minutes The machine breaks down at 117 minutes and takes 28 minutes to repair. Jobs are scheduled using Shortest Processing Time (SPT) first rule. What is the total completion time (makespan) after handling the breakdown?
Step-by-step solution (Breakdown Recovery):

1. Original SPT order: Job A → Job B → Job E → Job D
2. Simulate processing with breakdown:
- Job A: 0 → 30
- Job B: 30 → 87
- Job E: Starts at 87, breakdown at 117 (30 min completed), repair 28 min, resume 32 min → completes at 177
- Job D: 177 → 240

3. Total makespan: 240 minutes
4. Delay caused by breakdown: 28 minutes

Answer: 240 minutes

Key Strategy: Simulate the timeline, account for breakdown during active job processing.

Question 15

A machine needs to process 4 jobs. Processing times: - Job C: 38 minutes - Job E: 88 minutes - Job B: 52 minutes - Job A: 87 minutes The machine breaks down at 70 minutes and takes 45 minutes to repair. Jobs are scheduled using Shortest Processing Time (SPT) first rule. What is the total completion time (makespan) after handling the breakdown?
Step-by-step solution (Breakdown Recovery):

1. Original SPT order: Job C → Job B → Job A → Job E
2. Simulate processing with breakdown:
- Job C: 0 → 38
- Job B: Starts at 38, breakdown at 70 (32 min completed), repair 45 min, resume 20 min → completes at 135
- Job A: 135 → 222
- Job E: 222 → 310

3. Total makespan: 310 minutes
4. Delay caused by breakdown: 45 minutes

Answer: 310 minutes

Key Strategy: Simulate the timeline, account for breakdown during active job processing.

Question 16

A machine needs to process 4 jobs. Processing times: - Job B: 35 minutes - Job D: 38 minutes - Job E: 68 minutes - Job C: 52 minutes The machine breaks down at 100 minutes and takes 18 minutes to repair. Jobs are scheduled using Shortest Processing Time (SPT) first rule. What is the total completion time (makespan) after handling the breakdown?
Step-by-step solution (Breakdown Recovery):

1. Original SPT order: Job B → Job D → Job C → Job E
2. Simulate processing with breakdown:
- Job B: 0 → 35
- Job D: 35 → 73
- Job C: Starts at 73, breakdown at 100 (27 min completed), repair 18 min, resume 25 min → completes at 143
- Job E: 143 → 211

3. Total makespan: 211 minutes
4. Delay caused by breakdown: 18 minutes

Answer: 211 minutes

Key Strategy: Simulate the timeline, account for breakdown during active job processing.

Question 17

A machine needs to process 4 jobs. Processing times: - Job B: 66 minutes - Job A: 56 minutes - Job E: 57 minutes - Job D: 69 minutes The machine breaks down at 66 minutes and takes 37 minutes to repair. Jobs are scheduled using Shortest Processing Time (SPT) first rule. What is the total completion time (makespan) after handling the breakdown?
Step-by-step solution (Breakdown Recovery):

1. Original SPT order: Job A → Job E → Job B → Job D
2. Simulate processing with breakdown:
- Job A: 0 → 56
- Job E: Starts at 56, breakdown at 66 (10 min completed), repair 37 min, resume 47 min → completes at 150
- Job B: 150 → 216
- Job D: 216 → 285

3. Total makespan: 285 minutes
4. Delay caused by breakdown: 37 minutes

Answer: 285 minutes

Key Strategy: Simulate the timeline, account for breakdown during active job processing.

Question 18

A machine needs to process 4 jobs. Processing times: - Job C: 59 minutes - Job D: 76 minutes - Job A: 32 minutes - Job B: 72 minutes The machine breaks down at 106 minutes and takes 35 minutes to repair. Jobs are scheduled using Shortest Processing Time (SPT) first rule. What is the total completion time (makespan) after handling the breakdown?
Step-by-step solution (Breakdown Recovery):

1. Original SPT order: Job A → Job C → Job B → Job D
2. Simulate processing with breakdown:
- Job A: 0 → 32
- Job C: 32 → 91
- Job B: Starts at 91, breakdown at 106 (15 min completed), repair 35 min, resume 57 min → completes at 198
- Job D: 198 → 274

3. Total makespan: 274 minutes
4. Delay caused by breakdown: 35 minutes

Answer: 274 minutes

Key Strategy: Simulate the timeline, account for breakdown during active job processing.

Question 19

A machine needs to process 4 jobs. Processing times: - Job B: 30 minutes - Job C: 56 minutes - Job D: 69 minutes - Job E: 39 minutes The machine breaks down at 92 minutes and takes 17 minutes to repair. Jobs are scheduled using Shortest Processing Time (SPT) first rule. What is the total completion time (makespan) after handling the breakdown?
Step-by-step solution (Breakdown Recovery):

1. Original SPT order: Job B → Job E → Job C → Job D
2. Simulate processing with breakdown:
- Job B: 0 → 30
- Job E: 30 → 69
- Job C: Starts at 69, breakdown at 92 (23 min completed), repair 17 min, resume 33 min → completes at 142
- Job D: 142 → 211

3. Total makespan: 211 minutes
4. Delay caused by breakdown: 17 minutes

Answer: 211 minutes

Key Strategy: Simulate the timeline, account for breakdown during active job processing.

Question 20

A machine needs to process 4 jobs. Processing times: - Job A: 55 minutes - Job B: 65 minutes - Job D: 58 minutes - Job C: 82 minutes The machine breaks down at 103 minutes and takes 27 minutes to repair. Jobs are scheduled using Shortest Processing Time (SPT) first rule. What is the total completion time (makespan) after handling the breakdown?
Step-by-step solution (Breakdown Recovery):

1. Original SPT order: Job A → Job D → Job B → Job C
2. Simulate processing with breakdown:
- Job A: 0 → 55
- Job D: Starts at 55, breakdown at 103 (48 min completed), repair 27 min, resume 10 min → completes at 140
- Job B: 140 → 205
- Job C: 205 → 287

3. Total makespan: 287 minutes
4. Delay caused by breakdown: 27 minutes

Answer: 287 minutes

Key Strategy: Simulate the timeline, account for breakdown during active job processing.
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