a) Current population =P(c)
Future population =P(f)
P(f) =P(c) x e^(rt), where r= Rate of growth, t =Number of years.
70,000,000 = 35,000,000 x e(0.082t) Divide both sides by 35,000,000
2 = e^0.082t Take the natural log of both sides
t = ln(2) / 0.082
t =~ 8.45 - years for the population of the country to double.
b) e^.082 =1.0854558..... - 1 x 100 =~8.55% - the equivalent yearly rate of growth.