Based on the current rates of increase of 1.5% per year, the world population is projected to double from 7 billion ina.46 yearsb.10 yearsc.15 yearsd.100 years

To find out how long it will take for the world population to double at a growth rate of 1.5% per year, we can use the Rule of 70, which is a quick way to estimate the doubling time of a population based on a constant growth rate.

Break Down the Problem

1. Identify the growth rate: 1.5% per year.
2. Determine the doubling time using the Rule of 70.

Relevant Concepts

The Rule of 70 states that the doubling time (in years) can be approximated by dividing 70 by the annual growth rate (as a percentage): \text{Doubling Time} \approx \frac{70}{\text{growth rate (in %)}}

Analysis and Detail

1. Apply the Rule of 70: $\text{Doubling Time} \approx \frac{70}{1.5} \approx 46.67 \text{ years}$

Verify and Summarize

The doubling time calculated using the Rule of 70 gives approximately 46.67 years, which we can round to 46 years for simplicity.

Final Answer

The projected time for the world population to double from 7 billion at a growth rate of 1.5% per year is approximately 46 years. The correct answer is a. 46 years.