Question

The population increases by 5% every year. Find the increase in the population in 2 years if the original population was 1,50,000

Answer 1

let population be  P two years ago. 

Then  last year it became, 5% more.  So  P + 5/100 * P = 105/100 * P

This year it has become = 105/100 * P + [105/100*P] * 5/100
               = P * 105/100* 105/100
this amount is equal to  1,50, 000
      P = 1,50,000 * 100 * 100 / (105 * 105)
             = 1, 36, 054.4

Answer 2

The population after two years will be,
             150000(1+(5/100))²
            =150000(105/100)²
           =15*105*105
               =1,65,375

So the increase in population will be 15,375