### 1. Find the compound interest on Rs. 6,500 for 4 years if the rate of interest is 10% p.a. for the first 2 years and 20% per annum for the next 2 years?

### 2. What is the interest rate per annum, if a sum of money invested at compound interest amount to Rs. 2400 in 3 years and in 4 years to Rs. 2,520?

### 3. A sum is equally invested in two different schemes on CI at the rate of 15% and 20% for two years. If interest gained from the sum invested at 20% is Rs. 528.75 more than the sum invested at 15%, find the total sum?