# Scientists Use the Rule of 707070 to Calculate Human Population Growth

## Explanation

**The rule of 70** is used to find the approximate doubling time in years. The rule of 70 uses the equation 70 divided by the growth rate per year. In this case, with a population growth rate of 10%, the calculation would be 70/10 = 7. This means that the population would double in 7 years.

Therefore, for a nation with a population growth rate of 10% per year, the doubling time would be 7 years.