Question

the present population of a city is 9261000. if it is increasing by 5% per annum. find its population 3 years ago.

Answer 1

The population 3 yrs ago was 4,741,632..
(Solved by the Forlmula of Uniform Rate of Increase or Decrease)

Answer 2

The population of the city 3 years ago was 791448.

• Given:

The population is increasing at a rate of 5% pa.

The current population of a city is 9261000.

• Now , we have to find the population of the city 3 years ago.

Population after n years = $P (1+\frac{R}{100})^n$,

where P is the population R is the rate and n is the number of years.

• Substituting the known values , we get

9261000 =  $P (1+\frac{5}{100})^3$

9261000 =  $P (\frac{21}{20})^3$

P = 791448

• The population of the city 3 years ago was 791448.