If the original population of a locality be P and the annual growth rate be r%, then the population of the locality after n years-
$(= P{\left( {1 + \frac{r}{{100}}} \right)^n})$
The population of a city increases at the rate of 4% per annum. There is an additional increase of 1% per annum due to influx of job seekers.
According to the question, total percentage increase = (4 + 1)% = 5%
Let initial population = 100,
∴ Population after 2 years $(= 100{\left( {1 + \frac{5}{{100}}} \right)^2} = 100{\left( {\frac{{21}}{{20}}} \right)^2} = \frac{{441}}{4} = 110.25)$
Increase in population = 110.25 – 100 = 10.25
∴ Percent increase = (10.25/100) × 100% = 10.25%
Hence, the required percentage increase in the population of the city is 10.25%.Let the population of the city be 100
By question, increase in population% annually is 5%
Therefore , after 1st year the population becomes 105
After 2nd year the population become:105+5/100×105=105+21/4=105+5.25=110.25
Hence, population increase after to year is 110.25-100=10.25.which is 10.25%(10.25/100×100)%