A man deposited Rs. 10,000 in a bank at the rate of 5% simple interest annually. Find the amount in 15th year since he deposited the amount and also calculate the total amount after 20 years.
Original cost of scooter = Â Rs. 22000
Amount paid in cash   =  Rs. 4000
Amount to be paid in instalments = Â Rs. 18000
Let a denote the first instalment
                 a = 1000 + 10% interest on unpaid amount
                  =  Rs .
               a = Rs. 2800
   2nd instalment =Â
  Similarly, 3rd instalment  = Rs. 2600
∴  Various instalments are Rs. 2800, Rs. 2700, Rs. 2600.........
Amount paid in instalments = Rs. 2800 + Rs . 2700 + Rs . 2600 + ......+ Rs. 1100
                  = Rs .Â
                                 Â
                  = Rs. 9[5600 - 1700] = Rs. 9(3900) = Rs. 35100
Actual amount by Hari    = Rs. [35100 + 4000] = Rs 39100