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22/01/2022 6:04 pm
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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
(a) 25 millions
(b) 17 millions
(c) 20 millions
(d) 18 millions
1 Answer
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22/01/2022 6:09 pm
Correct answer: (b) 17 millions
Explanation:
\(\frac{dN}{dt}\) = rN
r = 0.028 - 0.008 = 0.02
dt = 2015 - 2005 = 10 years
N = N2005 = 14 million
dN = change in population in 10 years
\(\frac{dN}{dt}\) = 0.02 x 14
dN = 0.02 x 14 x 10
dN = 2.8 million
dN = N2015 - N2005
N2015 = dN + N2005
= 2.8 + 14
= 16.8 ≃ 17 million