Plant Operator Selection System Mathematical Usage Problems Flashcards

A plant operates 330 days per year. If production averages 1,250 units per day, how many units are produced annually?

Answer: 412,500

1,250 × 330 = 412,500 units per year.

A worker uses 2/3 of a container of lubricant on Machine A and 1/6 of the same container on Machine B. What fraction of the container remains?

Answer: 1/6

2/3 + 1/6 = 4/6 + 1/6 = 5/6 used; 1 − 5/6 = 1/6 remaining.

A pipe leaks at a rate of 0.5 gallons per minute. How many gallons are lost in a 40-hour work week?

Answer: 1,200 gallons

0.5 gpm × 60 × 40 = 0.5 × 2,400 = 1,200 gallons.

An operator reads a flow of 45 cubic feet per minute. Approximately how many gallons per minute is this? (1 cu ft ≈ 7.48 gallons)

Answer: 337 gpm

45 × 7.48 = 336.6 ≈ 337 gpm.

A batch reactor requires 3 hours 45 minutes per cycle. How many complete cycles can be run in a 24-hour period?

Answer: 6 cycles

3 hr 45 min = 3.75 hr; 24 ÷ 3.75 = 6.4, so 6 complete cycles.

A solution requires a specific gravity of 1.15. If pure water weighs 8.34 lbs/gallon, how much does one gallon of the solution weigh?

Answer: 9.59 lbs

8.34 × 1.15 = 9.591 ≈ 9.59 lbs/gallon.

If 1 inch on a plant diagram equals 25 feet in actual distance, what is the actual distance represented by 3.6 inches on the diagram?

Answer: 90 feet

3.6 × 25 = 90 feet.