In this case we would use the Rule of 72 to calculate the doubling time for each country. (Remembering to present it as a whole number)
Compute the doubling time for France's per capita real GDP. 72/1.9% = 37.8947 or approximately 38 years
Compute the doubling time for Korea's per capita real GDP. 72/4.2% = 17.1428 or 17 years
What will France's per capita real GDP be in 2045?
What will Korea's per capita real GDP be in 2045?