Word Problems 1
Problem 1: During one year the population of a town increased 5% and during the next it decrease 5%. At the end of the second year the population was 49875. What was the population at the beginning of the first year?
We use here formulas of compound interest for increment and decrement.
for increment the formula is;
and for decrement the formula is ;
Data for first year can be arranged as under;
Principal population P = x
Rate of increase R=5%
Term T = 1 Year
Population at the end of 1st Year A=?
As population increase during first year, put these values in formula(1) above;
So Population at the end of 1st year is whch will now be the principal population for 2nd year:
Principal population P=
Rate of decrease R = 5%
Term T = 1 year
Population at the end of 2nd year A =?
As population decreases during 2nd year, put these values in formula (2) above;
Thus population at the end of 2nd year is . But population as given at the end of 2nd year is 49875
So population in the beginning was 50000