City Guilds Model Questions Vol1 2025 Engineering Question 17

Practice objective / multiple choice question 17 from the 2025 City Guilds Model Questions Vol1 Engineering examination.

City Guilds Model Questions Vol1 2025 Engineering Objective / Multiple Choice Hard Difficulty
Question 17 CITY_GUILDS_MODEL_QUESTIONS_VOL1 • 2025 • ENGINEERING • objective

A machine has a constant failure rate of \(\lambda = 0.02\) h\(^{-1}\) (exponential distribution). A preventive maintenance (PM) action costs \(\text{₦}500\) and requires 1 h of downtime. An unexpected failure costs \(\text{₦}3000\) and results in an average downtime of 4 h. If a preventive maintenance interval of \(T\) hours is adopted, the expected cost per hour is given by \[\frac{C_{\text{PM}} + C_{\text{F}}\,P_f}{e^{-\lambda T}(T+1) + P_f\bigl(E[t\mid t

Answer Options

Correct Answer A. Run‑to‑failure (no preventive maintenance); minimum expected cost ≈ ₦65 per hour.
B. Preventive maintenance every 20 h; minimum expected cost ≈ ₦80 per hour.
C. Run‑to‑failure; minimum expected cost ≈ ₦75 per hour.
D. Preventive maintenance every 10 h; minimum expected cost ≈ ₦70 per hour.
Correct Answer
A
Correct Option:
Run‑to‑failure (no preventive maintenance); minimum expected cost ≈ ₦65 per hour.

About This Question

This is City Guilds Model Questions Vol1 2025 Engineering Question 17. It is one of the objective questions from the 2025 City Guilds Model Questions Vol1 Engineering examination.

Difficulty level: Hard .

View More City Guilds Model Questions Vol1 2025 Engineering Questions More City Guilds Model Questions Vol1 Practice Questions Back to Questions

Master the Exam!

You've seen a preview, but there are thousands more questions plus AI tutor to break down complex solutions.

Unlock Full Access Available for Android & Windows
Chat with Support