The problem asks for the annual interest rate (R) given the principal amount (P), time period (T), and the difference between compound interest (CI) and simple interest (SI) for that period.
For a period of 2 years, the difference between compound interest and simple interest is given by the formula:
$ \text{CI} - \text{SI} = P \left( \frac{R}{100} \right)^2 $
Where:
Therefore, the rate of interest per annum is 4%.
Find the interest (in ₹) on ₹8,000 at 10% per annum compounded half yearly for $1\frac{1}{2}$ years.
The difference between the simple interest and the compound interest, compounded annually, on a certain sum of money for 2 years at 17% per annum is ₹967. Find the sum [rounded off to the nearest integer].