Question

Question 91

The population of a town was decreasing every year due to migration, poverty and unemployment. The present population of the town is 631680. Last year the migration was 4% and the year before last, it was 6%. What was the population two years ago ?

Answer 1

Let the population two years ago = P (Principal)
Present population of the town = A = 631680
Rate of migration in Ist year = 4%
Rate of migration in IInd year = 6%
By using the formula, $A=P(1-\frac{R}{100})(1-\frac{R}{100})\Rightarrow 631680=P(1-\frac{4}{100})(1-\frac{6}{100})\Rightarrow 631680=P\times \frac{24}{25}\times \frac{47}{50}\Rightarrow P=\frac{631680\times 25\times 50}{24\times 47}\Rightarrow =560\times 1250=700000$
Hence, the population of town was 700000 two years ago.