At 1.2%, the number of years required to double is calculated as :
2= 1*(1+0.012)^n
2 = 1.012^n
log 2 = n log 1.012
n = log 2/log 1.012 = 58.11 Years
At a 1.2% annual percentage rate, a population doubles in size in 58.11 years
At 2.8%, the number of years required to double is calculated as :
2= 1*(1+0.028)^n
2 = 1.028^n
log 2 = n log 1.028
n = log 2/log 1.028 = 25.10 Years
At a 2.8% annual percentage rate, a population doubles in size in 25.10 years