Question

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

Answer 1

Answer: (B)

17 millions

Exponential equation gives population growth rate as

$\frac{dN}{dt}=rN$

Here, r = Rate of natural increase

N = Size of original population

$\frac{dN}{dt}=$ Increase in population size per unit time (1 year in this case)

r is the difference between birth and death rate.

r = 0.028 - 0.008 = 0.02

$\dfrac {dN}{dt}= 0.02 x14 million = 0.28 million

over 10 years (2005 - 2015), this number will become = 2.8 miillion

Expected population in 2015 = (14+2.8) million

= 17 million (approx),

So, the correct answer is '17 millions'.