5. According to the most recent data available, there are currently 7,594,000,000 people on Earth, and our population is growing at a rate of 0.012 per year. Assuming that the world's population continues to grow at its current rate: A. How long would it take to grow by 50%? B. How long would it take to quadruple? C. How long would it take to add the next 1 billion? 6. According to the US Census Bureau, the US resident population was estimated to be 330,554,388 in the year 2020. The US population has a RNI of 0.30% per year (r=0.003). If the United States continues growing at this rate, in what calendar year will it reach 500,000,000 people? Hint: use the exponential growth formula to solve for n. 7. If a population is growing at a rate that would cause it to double in 55 years, how long would it take for that population to increase by half (ie, grow to 1.5 times its current size)? Hint: Use exponential growth formula - twice: First, solve for r. Then, use your calculated value of r to answer the question. 8. THINK, DISCUSS, AND SPECULATE IRRESPONSIBLY: Japan has a negative rate of natural increase of -2 per 1000. This would give a rate of change of -0.2% or r=-0.002. Is Japan at risk of complete depopulation? Why or why not