Q16 of 70 Page 88

In 2005, for each of the 14 million people present in a country, 0.028 were born and 0.008 died during the year. Using exponential equation, the number of people present in 2015 is predicted as:

The required exponential equation is,


Where N = Population size


t = time period


r = ‘intrinsic rate of natural increase’ = b-d


d = death rates


b = birth rates


From the given criteria,


N2005 = 14 million


b = 0.028


d = 0.008


r = b-d = 0.028 – 0008 = 0.020


dt = 2015 – 2005 = 10 years


Using exponential equation,




dN = 0.28×10 = 2.8


We know


dN = N2015- N2005


N2015= dN + N2005 = 2.8 + 14 = 16.8 ≈ 17 millions


Using exponential equation, the number of people present in 2015 is predicted as 17 millions.


Hence the correct answer is option (b).

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