Predicting Population Growth

 Predicting population growth that means predicting how much population will increase after 'n' years.

Annual population growth rate = ((Future population – Present population) / Present population) / N

      Where present population is the population at beginning period, future population is the population at end of period, N is the total number of years. Population growth rate used in economic, employment, unemployment.

In this article we will discuss about how to predict population growth.

 

Predicting Population Growth – Example Problems

 

Ex 1: A city has a population of 450000 and annual rate of growth is 10.5%. Find the population after 10 years.

Sol:

Present population = 450000

Future population = x

Number of years = 10

Formula: Annual population growth rate = ((Future population – Present population) / Present population) / N

`10.5 / 100` = `(((x - 450000) / 450000)) / 10 ` 

1.05 = `((x - 450000) / 450000)` 

472500 = x - 450000

x = 922500

Therefore, after 10 years population of a city will be increase as 922500.

 Ex 2: A country has a population of 5487000 and annual rate of growth is 14.3%. Find the population after 8 years.

Sol:

Present population = 5487000

Future population = x

Number of years = 8

Formula: Annual population growth rate = ((Future population – Present population) / Present population) / N

`14.3 / 100` = `(((x - 5487000) / 5487000)) / 8 ` 

1.144 = `((x - 5487000) / 5487000)` 

6277128 = x - 5487000

x = 11764128

Therefore, after 8 years population of a country will be increase as 11764128.

 

Ex 3: A village has a population of 5400 and annual rate of growth is 9.5%. Find the population after 5 years.

Sol:

Present population = 5400

Future population = x

Number of years = 5

Formula: Annual population growth rate = ((Future population – Present population) / Present population) / N

`9.5 / 100` = `(((x - 5400) / 5400)) / 5 ` 

0.475 = `((x - 5400) / 5400)` 

2565 = x - 5400

x = 7965

Therefore, after 5 years population of a village will be increase as 7965.

 

Predicting Population Growth – Practice Problems

 

Pr 1: A city has a population of 620000 and annual rate of growth is 4.83%. Find the population after 9 years.

Pr 2: A country has a population of 256400 and annual rate of growth is 15.8%. Find the population after 7 years.

Ans: 1) 890000 2) 540000