FE Other Disciplines Practice Question Solution included after investigation
CASE E-094 · FE

The Upgrade Worth $3,675, Not $25,000

Undiscounted cash flows suggested a $25,000 gain; discounted NPV is about $3,675.

▶ INTERACTIVE CASE FILE • 5–10 MIN • CLICK TO INVESTIGATE

Inspect, commit, prove, fix, and sign off.

Case E-094 engineering failure visual
HOW THIS WORKS

Think like
a real engineer.

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 upgrade costs $75,000 now, saves $18,000 at each year-end for 5 years, and has $10,000 salvage in year 5. At 8%, determine benefit present worth and NPV.

Engineering Economics Other Disciplines Design Verification Root Cause Analysis Safe Correction
E-094
INVESTIGATION WORKSPACE WORK THROUGH THE CASE — YOUR CHOICES MATTER.
🔒
DEBRIEF (LOCKED)

Complete the investigation
to unlock the full debrief.

Find the root cause, confirm the fix, and see how this connects to the exam.

🔒Root causeComplete the case
to reveal
🔒Correct fixComplete the case
to reveal
🔒Exam takeawayComplete the case
to reveal
CASE CLOSED · ENGINEERING VERDICT

What actually failed — and what should change.

What failed

Nominal future dollars were compared with present cost.

What was missed

Time value of money.

Corrected model

Discount future benefits, then subtract initial cost.

QUICK ANSWER

At 8%, savings PW is about $71,868.8 and salvage PW about $6,805.8. Benefit PW is about $78,674.6, giving NPV about $3,674.6.

ENGINEERING TAKEAWAY

Discount future cash flows to time zero before comparison.

CASE QUESTIONS

Questions this case should settle.

What does positive NPV mean?

Discounted benefits exceed discounted costs at the stated rate.

Should salvage value be discounted?

Yes, if it occurs in a future year.

NEXT FE PRACTICE QUESTION

The Risky Project Worth $52,000, Not $35,000

Engineering Economics · 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?

Most cases are designed for a focused 5–10 minute investigation.

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.