In case of compound interest, the rate of compound interest per annum is-

As a result of continuous publicity on harmful reactions in the use of cold drinks filled, bottles, the number of users of cold drinks is decreased by 25% every year in comparison to its previous year. 3 years before number of users of cold drink in a town was 80000. Let us write by calculating, the number of users of cold drink in the present year.

As a result of publicity on smoking, the number of smoker is decreased by % every year in comparison to its previous year. If the number of smokers at present in a city is 33750, let us write by calculating, the number of smoker in the city 3 years before.

In case of compound interest

At present the population of a village is p and if increase rate of population per year be 2r%, the population will be after n years