ExxonMobil Test ExxonMobil Problem Solving 2 — Questions and Answers
Question 1: You are given data: Plant A produces 500 units with 10 defects; Plant B produces 800 units with 14 defects. Which plant has a better defect rate?
- Plant A, with 2.0% defect rate
- Plant B, with 1.75% defect rate (Correct answer)
- Plant A, with 2.5% defect rate
- Both plants have the same defect rate
Correct answer: Plant B, with 1.75% defect rate
Plant A: 10/500 = 2.0%; Plant B: 14/800 = 1.75%; Plant B has a lower defect rate.
Question 2: A safety audit finds 3 critical, 7 major, and 12 minor non-conformances. Using risk prioritization, which should be addressed first?
- The 12 minor findings, as they represent the most work
- The 3 critical findings, as they pose the greatest risk (Correct answer)
- All findings simultaneously to show commitment to safety
- The 7 major findings, as they represent the largest single category
Correct answer: The 3 critical findings, as they pose the greatest risk
Risk-based prioritization always addresses critical findings first because they pose the greatest potential for harm.
Question 3: A control room operator observes two alarms simultaneously: high pressure in Vessel A and low level in Vessel B. These vessels are connected by a transfer line. What is the most logical conclusion?
- Both instruments are malfunctioning at the same time
- The transfer line between the vessels is blocked or closed (Correct answer)
- Vessel A has a leak and Vessel B has a level sensor fault
- The vessels are operating normally and alarms are routine
Correct answer: The transfer line between the vessels is blocked or closed
Simultaneous high pressure in the sending vessel and low level in the receiving vessel strongly suggests the transfer line is blocked or the valve is closed.
Question 4: Production costs are: labor $120,000, materials $340,000, overhead $90,000, and energy $50,000. If a 15% cost reduction is required, which area should be prioritized?
- Labor, as it has potential for workforce reduction
- Materials, as it is the largest cost component (Correct answer)
- Energy, as it is the easiest to reduce
- Overhead, as it is a discretionary cost
Correct answer: Materials, as it is the largest cost component
Materials at $340,000 is the largest cost component; a 15% reduction in materials yields the greatest absolute savings.
Question 5: An ExxonMobil manager must choose between two projects. Project X has NPV of $2.1M with 70% probability of success; Project Y has NPV of $3.5M with 40% probability. Which has the higher expected value?
- Project X, with expected value of $1.47M (Correct answer)
- Project Y, with expected value of $1.4M
- Both projects have the same expected value
- Project X, with expected value of $2.1M
Correct answer: Project X, with expected value of $1.47M
Project X: $2.1M × 0.70 = $1.47M; Project Y: $3.5M × 0.40 = $1.4M; Project X has a higher expected value.
Question 6: A process diagram shows that Stream C is produced when Streams A and B are combined and heated. If Stream C has abnormally high impurities, where should the investigation begin?
- The heating equipment
- Both Stream A and Stream B quality simultaneously (Correct answer)
- The storage tank receiving Stream C
- The quality testing laboratory
Correct answer: Both Stream A and Stream B quality simultaneously
If the product (Stream C) is contaminated, the logical starting point is examining both input streams (A and B) for impurity sources.
ExxonMobil Test ExxonMobil Problem Solving 2
You are given data: Plant A produces 500 units with 10 defects; Plant B produces 800 units with 14 defects.
Which plant has a better defect rate?