Final answer:
To determine the time required for a population to double with a 2% growth rate, you use the Rule of 70, which yields approximately 35 years for the doubling time.
Step-by-step explanation:
To calculate how long it will take for a population to double with a growth rate of 2%, we can use the Rule of 70. This rule is a shortcut to estimate the number of years it will take for a quantity to double when it is growing exponentially at a steady rate. The Rule of 70 states that you can divide 70 by the annual growth rate to get the doubling time in years.
For a 2% growth rate, we calculate the doubling time as follows:
- Divide 70 by the growth rate: 70 / 2% = 70 / 0.02.
- Carry out the division: 70 / 0.02 = 35 years.
The population will therefore take approximately 35 years to double at a growth rate of 2%. This is consistent with the historical data mentioned in your question, which reflects a doubling time of 36 years between 1965 and 1980 when the growth rate was 2%. However, it's important to recognize that changes in the growth rate will affect the doubling time accordingly.