4. Calculate the population doubling time of a given country with annual rate of growth ( r) = 1% .
Current Population=CP
Future Population =FP
FP=CP x 1.01^x
2 = 1 x 1.01^x take the log of both sides
x =Log(2) / Log(1.01)
x=69.66 years that it will take the population to double @ 1%
