Simple and Compound Interest Problems with Solutions

Before going to the simple interest and compound interest problems, you should revise the simple and compound interest formulas. After revising the formulas you will understand the following examples.
Example 1:If the difference between Simple Interest and Compound Interest on a certain sum of money in 2 years at 20 % p.a. is Rs. 800, then find the sum.
Example 2:The compound interest on a certain sum of money for 2 years is Rs. 52 and the simple interest for the same time at the same rate is Rs. 50. Find the rate %.
Example 3:The difference between Compound Interest and Simple Interest on a certain sum of money at 10 % per annum for 3 years is Rs. 930. Find the principal if it is known that the interest is compounded annually.
Example 4:The population of a town has a constant growth of 4% p.a. If its present population is 62,500, what will be its population after two years?
Example 5:The cost of a new washing machine is Rs. 12000. Its value depreciates every year at the rate of 10%. What will be its value after three years?