Mohit invests ₹ 8000 for 3 years at a certain rate of interest, compounded annually. At the end of one year, it amounts to ₹ 9440. Calculate :

(i) the rate of interest per annum.

(ii) the amount at the end of the second year.

(iii) the interest accrued in the third year.

The compound interest, calculated yearly, on a certain sum of money for the second year is ₹ 1089 and for the third year it is ₹ 1197.90. Calculate the rate of interest and the sum of money.

The cost of a machine depreciated by ₹ 4000 during the first year and by ₹ 3600 during the second year. Calculate :

(i) the rate of depreciation.

(ii) the original cost of the machine.

(iii) its cost at the end of third year.

Ramesh invests ₹ 12800 for three years at the rate of 10% per annum compound interest. Find :

(i) the sum due to Ramesh at the end of the first year.

(ii) the interest he earns for the second year.

(iii) the total amount due to him at the end of third year.