Question

if the population is increasing at an annual rate of 1.3% and there were 5 billion people in the year 1986, then in what year will the world population reach 10 billion people

Answer 1

Based on the information given above, ignoring leap years and assuming the population was 5 billion at the very end of 1986, the population is predicted to reach 10 billion on 30 August in the year 2039. : )

Do you know how to take logarithms ?