The formula for exponential growth rate is:
A = Ao e^(k t)
where A is the final standard of living, Ao is the
initial, k is the growth rate constant in decimal = 0.08, t is time elapsed
So we will find t at A/Ao = 2
A/Ao = e^(k t)
2 = e^( 0.08 t)
t = 8.66 ~ since more than therefore 9
So by the time they reached age 29
