Plant Operator Selection System Test Plant Operator Selection System Mathematical Usage Problems 3 — Questions and Answers
Question 1: A rectangular settling pond is 200 feet long, 80 feet wide, and 6 feet deep. What is the volume in cubic feet?
- 48,000 cu ft
- 96,000 cu ft (Correct answer)
- 16,000 cu ft
- 9,600 cu ft
Correct answer: 96,000 cu ft
Volume = 200 × 80 × 6 = 96,000 cubic feet.
Question 2: A pressure gauge reads 85 psi. If atmospheric pressure is 14.7 psi, what is the absolute pressure?
- 70.3 psi
- 85.0 psi
- 99.7 psi (Correct answer)
- 114.7 psi
Correct answer: 99.7 psi
Absolute pressure = gauge pressure + atmospheric pressure = 85 + 14.7 = 99.7 psi.
Question 3: A flow meter shows 240 gallons per minute. How many gallons flow through in 2.5 hours?
- 600 gallons
- 6,000 gallons
- 36,000 gallons (Correct answer)
- 60,000 gallons
Correct answer: 36,000 gallons
240 gpm × 60 min/hr × 2.5 hr = 36,000 gallons.
Question 4: An operator mixes 15 pounds of chemical A with 45 pounds of chemical B. What percentage of the mixture is chemical A?
- 15%
- 25% (Correct answer)
- 33.3%
- 50%
Correct answer: 25%
15 ÷ (15 + 45) = 15 ÷ 60 = 0.25 = 25%.
Question 5: A temperature reading changes from 68°F to 212°F. What is the change in Celsius? (°C = (°F − 32) × 5/9)
- 60°C
- 80°C (Correct answer)
- 90°C
- 100°C
Correct answer: 80°C
Initial: (68−32)×5/9=20°C; final: (212−32)×5/9=100°C; change=80°C.
Question 6: A plant produces 3,600 units in an 8-hour shift. If production increases by 15%, how many units are produced per hour in the new rate?
- 450 units/hr
- 495 units/hr
- 517.5 units/hr (Correct answer)
- 540 units/hr
Correct answer: 517.5 units/hr
3,600 × 1.15 = 4,140 units per shift; 4,140 ÷ 8 = 517.5 units/hr.
Question 7: A valve allows flow to pass at 65% efficiency. If the pump delivers 400 gallons per minute, how many gallons per minute actually pass through the valve?
- 140 gpm
- 200 gpm
- 260 gpm (Correct answer)
- 340 gpm
Correct answer: 260 gpm
400 × 0.65 = 260 gpm.
Plant Operator Selection System Test Plant Operator Selection System Mathematical Usage Problems 3
A rectangular settling pond is 200 feet long, 80 feet wide, and 6 feet deep.
What is the volume in cubic feet?