643 e^10k = 813
e^10k = 813/643 = 1.2644
10k = ln 1.2644 = 0.2346
k = 0.02346
now just solve for t in
643 e^0.02346t = 2x10^9
In 1990, the population of Africa was 643 million and by 2000 it had grown to 813 million.
a.) Use the exponential growth model A=A0 e^kt, in which t is the number of years after 1990, to find the exponential growth function that models the data.
b.) By which year will Africa population reach 2 billion?
1 answer