To solve this, we use the formula for exponential growth based on the doubling time:

$P = P_0 \times 2^{\frac{t}{T}}$

where:

• $P_0$ is the initial population (7.1 billion),
• $T$ is the doubling time (49 years),
• $t$ is the time elapsed since the initial year (2013).

Part 2: Calculating for 2061

1. Determine $t$ for the year 2061: $t = 2061 - 2013 = 48 \text{ years}$

2. Apply the formula: $P = 7.1 \times 2^{\frac{48}{49}}$

Let's calculate this:

$P \approx 7.1 \times 2^{0.9796} \approx 7.1 \times 1.978 \approx 14.1 \text{ billion}$

Answer:

The population in 2061 will be approximately 14.1 billion.

Would you like further details on the calculations, or do you have additional questions?

Here are five related questions you might find interesting:

1. How would the population change if the doubling time was 60 years instead?
2. What would be the population in 2119 if the initial population was higher?
3. How does exponential growth differ from linear growth in population predictions?
4. How would a declining growth rate impact the predictions for future populations?
5. What are the implications of exponential growth on resource consumption?

Tip: When using exponential models, understanding the doubling time helps to quickly estimate population increases over time.