The compound interest on a certain sum for 2 years is Rs. 756 and simple interest is Rs. 720. Now, If the sum is invested such that the SI is Rs. 1296 and the number of years is equal to the rate percentage per year, then find the rate per cent:
It is given that simple interest for 2 years = Rs. 720
So, for 1 year = Rs. 7202 = Rs. 360 (because it is SI)
Compound Interest for 2 year = Rs. 756
Difference in the interest = Rs. 36 (756-720)
This difference is the interest on the interest of the first year.
So rate of interest =(36360)×100=10%
Now the interest for 1st Year = Rs. 360 at 10% SI
So, principal for 1st year = Rs. 3600
We have, SI=(P×R×T)100
3600×k2100=1296
k = 6