your method for b and c is based on approximations so its hard to comment. If those methods are allowed by your teacher then your answers are fine.
Okay.Japan's real GDP was 525 trillion yen in 2009, and 535 trillion yen in 2010. Japan's population was 127.6 million in 2009 and 127.5 million in 2010. Calculate
a. The economic growth rate
b. The growth rate of real GDP per person.
c. The approximate number of years it takes for real GDP per person in Japan to double if the real GDP economic growth rate returns to 3 percent a year and the population growth rate is maintained.
Answer to A is [(535-525)/525] * 100 = 1.9%
Answer to B is "Growth rate of real GDP - Growth rate of population".
The growth rate of population is [(127.5-127.6)/127.6] * 100 = -0.07837%.
Hence, the answer is 1.9% - (-0.07837%) = 1.97837% per person.
I need help with solving part c.
Use Rule of 70. First we have to recalculate the growth rate of real GDP per person since the economic growth rate is different.
Growth rate of real GDP per person = 3% - (-0.07837%) = 3.07837%
So the years it takes is 70 / 3.07837 = 22.74 years
Is this correct?