FE Industrial & Systems Practice Question Solution included after investigation
CASE E-081 · FE

The Assembly Line That Needed 4 Stations, Not 3.6

The arithmetic produced 3.6 stations, but a production line cannot operate with a fraction of a station. The theoretical minimum was 4.

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Case E-081 engineering failure visual
HOW THIS WORKS

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Follow the investigation process used in the field — in five guided steps.

1

Inspect

Review the problem, diagram, and evidence.

2

Commit

Choose your hypothesis.

3

Prove

Run calculations and test your idea.

4

Fix

Select and validate a safe correction.

5

Sign Off

See the full debrief and key takeaways.

Case Brief

SAME PRINCIPLES. HIGHER STANDARDS.
PROBLEM STATEMENT

An assembly line has 450 productive minutes available per shift and must produce 225 units per shift. The sum of all elemental task times is 7.2 minutes per unit. A planning note calculates 7.2/2.0=3.6 and reports that 3.6 stations are required. Determine the required cycle time, the theoretical minimum number of stations, and the line efficiency if four stations are used.

Manufacturing Service Production Systems Industrial Systems Design Verification Root Cause Analysis Safe Correction
E-081
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CASE CLOSED · ENGINEERING VERDICT

What actually failed — and what should change.

What failed

A fractional workload ratio was reported as a feasible workstation count.

What was missed

Workstations are discrete resources and must provide enough capacity within each cycle.

Corrected model

Use C=available time/demand and Nmin=ceil(total task time/C).

QUICK ANSWER

Cycle time is 450/225=2.0 min/unit. The workload ratio is 7.2/2.0=3.6, so the theoretical minimum is 4 stations. With four stations, line efficiency is 7.2/(4×2.0)=90%.

ENGINEERING TAKEAWAY

Calculate cycle time as available production time divided by required output, divide total task time by cycle time, then round up to the next whole workstation.

CASE QUESTIONS

Questions this case should settle.

How do you calculate assembly-line cycle time?

Divide available production time by required output.

Why is 3.6 workstations rounded up to 4?

Because workstation count is discrete and three stations would not provide enough work capacity per cycle.

NEXT FE PRACTICE QUESTION

The Inventory Policy That Ordered 707 Units, Not 10,000

Manufacturing Service Production Systems · 5–10 min

Continue Practice →
WHAT YOU’LL LEARN

Real failures. Lasting skills.

Each case is designed to build the judgment, analysis, and confidence you need for engineering exams — and beyond.

  • Apply core engineering concepts to real-world problems
  • Practice structured troubleshooting and analysis
  • Strengthen exam-ready thinking through realistic scenarios
COMMON QUESTIONS
Do I need prior knowledge to use these cases?

Basic subject familiarity helps, but every case is designed to teach through the investigation itself.

How long does a case take?

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Are the cases aligned with engineering exams?

Each case is mapped to a verified exam, subject, topic, and misconception before publication.

What happens after I complete a case?

The sealed debrief unlocks with the root cause, corrected reasoning, fix, and takeaway.