Industrial Maintenance Technician Practice Test

Lowering the thermostat from 75 degrees to 65 degrees results in a direct decrease in the air temperature by 10 degrees. To understand the percentage change, you would calculate the difference based on the original temperature. The formula for determining the percentage decrease is:

\[

\text{Percentage decrease} = \left( \frac{\text{original temperature} - \text{new temperature}}{\text{original temperature}} \right) \times 100

\]

Plugging in the values:

\[

\text{Percentage decrease} = \left( \frac{75 - 65}{75} \right) \times 100 = \left( \frac{10}{75} \right) \times 100 \approx 13.33\%

\]

This calculation shows that the air temperature is approximately 13.33 percent cooler than before, which closely aligns with the option of being at least 10 percent cooler. The other options misunderstand the concept of temperature change. For instance, stating that the air will be 5 percent cooler significantly underestimates the change, while saying it will remain the same or that it is 15 percent cooler does not accurately reflect the precise decrease, which falls between those values.