Plant Operator Selection System Test Plant Operator Selection System Tables and Graphs Interpretation 4

Question 1

A table shows chemical feed rates needed at different flow levels: 100 gpm→2.0 lb/hr, 200 gpm→4.0 lb/hr, 300 gpm→6.0 lb/hr. If the current flow is 250 gpm, what feed rate is required?

Accepted Answer

5.0 lb/hr

Answer

The ratio is 0.02 lb/hr per gpm, so 250 × 0.02 = 5.0 lb/hr.

Question 2

A dual-axis graph plots temperature (°F, left axis) and pressure (psi, right axis) over time. When temperature spikes at 2pm, pressure shows a corresponding dip. This indicates:

Accepted Answer

An inverse relationship between temperature and pressure at that time

Answer

When one variable increases while the other decreases at the same moment, they show an inverse (negative) relationship.

Question 3

A maintenance frequency table shows: Pump A serviced every 500 hours, Pump B every 750 hours, Pump C every 1,000 hours. After 3,000 hours of operation, how many total service events have occurred across all three pumps?

Accepted Answer

13

Answer

Pump A: 3000/500=6; Pump B: 3000/750=4; Pump C: 3000/1000=3; total = 6+4+3 = 13.

Question 4

A histogram shows the distribution of particle sizes in a batch. The tallest bar is at the 50–60 micron range. This bar represents the:

Accepted Answer

Mode

Answer

The tallest bar in a histogram represents the most frequently occurring value range, which is the mode.

Question 5

A trend graph shows that tank level has been declining at a constant rate of 3 inches per hour. The tank is currently at 48 inches. At this rate, when will it reach the low-level alarm set at 12 inches?

Accepted Answer

12 hours

Answer

(48 − 12) / 3 = 36 / 3 = 12 hours until the alarm level is reached.

Plant Operator Selection System Test Practice Test

Plant Operator Selection System Test Practice Test

Plant Operator Selection System Test Plant Operator Selection System Tables and Graphs Interpretation 4