To determine the population growth rate, we need to follow these steps:
1. Calculate the birth rate: The birth rate is the number of births divided by the initial population.
[tex]\[
\text{Birth rate} = \frac{\text{Number of births}}{\text{Initial population}}
\][/tex]
Given the numbers:
[tex]\[
\text{Birth rate} = \frac{100}{1000} = 0.10
\][/tex]
2. Calculate the death rate: The death rate is the number of deaths divided by the initial population.
[tex]\[
\text{Death rate} = \frac{\text{Number of deaths}}{\text{Initial population}}
\][/tex]
With the provided information:
[tex]\[
\text{Death rate} = \frac{200}{1000} = 0.20
\][/tex]
3. Determine the population growth rate: The population growth rate is the difference between the birth rate and the death rate.
[tex]\[
\text{Population growth rate} = \text{Birth rate} - \text{Death rate}
\][/tex]
Substituting the calculated values:
[tex]\[
\text{Population growth rate} = 0.10 - 0.20 = -0.10
\][/tex]
Therefore, the correct equation showing how to calculate the population growth rate is:
[tex]\[
\boxed{0.10 - 0.20 = -0.10}
\][/tex]
This corresponds to option C.
