The compound interest earned in two years at 8% per annum is Rs. 4160. What is the sum (in Rs.) invested?
On a sum of Rs. P at a rate of R% p.a. after n years,
Compound interest = P[(1 + R/100)n - 1]
Let the sum invested be Rs. P
⇒ CI = 4160 = P[(1 + 8/100)2 - 1]
⇒ 4160 = P[0.1664]
⇒ P = 4160/0.1664 = Rs. 25000
∴ The sum invested is Rs. 25000