A sum of money on compound interest amounts to Rs.10648 in 3 years and Rs.9680 in 2 years. The rate of interest per annum is :
1). 5%
2). 10%
3). 15%
4). 20%
Here is the right answer
Let the sum be P and rate of
interest be R% per annum. Then
p$(1+\frac{(R)^{2}}{100})$ = 9680 ...(i)
p$(1+\frac{(R)^{3}}{100})$....(ii)
On dividing equation (ii) by (i)
R = $\frac{1}{10}\times 100$
= 10%
HOW WE CALCULATE THIS BY FINDING THE INTEREST OF 1 YEAR