To calculate the unemployment rate, use the formula:
\[ \text{Unemployment Rate} = \frac{\text{Number of Unemployed}}{\text{Labor Force}} \times 100 \]
First, determine the number of unemployed residents:
\[ \text{Number of Unemployed} = \text{Labor Force} - \text{Employed} = 4,000 - 3,500 = 500 \]
Next, plug the number of unemployed into the unemployment rate formula:
\[ \text{Unemployment Rate} = \frac{500}{4,000} \times 100 = 12.5% \]
Therefore, the unemployment rate is 12.5%.
The correct response is 12.5% or 12.5 percent.