The height of tree increases at the rate of 20% every year. If the present height of tree is 28.8 metre, let us calculate the height of tree 2 years before.

Through publicity of road-safety programme, the street accidents in Purulia district are decreased by 10% in comparison to its previous year. If the number of street accidents in this year be 8748, let us write by calculating, the number of street accidents 3 years before in the district.

A cooperative society of fisherman implemented such an improved plan for the production of fishes that the production in a year will be increased 10% in comparision to its previous year. In the present year if the cooperative society can produce 406 quintals of fishes, let us write by calculating, what will be the production of fishes after 3 years.

Three years before from today a family had planned to reduced the expenditure of electric bill by 5% in comparison to its previous year. 3 year before, that family had to spend ₹4000 in a year for electric bill. Let us write by calculating how much amount will the family have to spend to pay the electric bill in the present year.

Weight of Savan babu is 80kg. In order to reduces his weight, he started regular morning walk. He decided to reduce his weight every year by 10%. Let us write by calculating, his weight after 3 years.