In what time will Rs.1,000 become Rs.1,331 at an interest rate of 10% per annum compounded annually?

Correct option is C

Given:

Principal (P) = Rs.1,000

Amount (A) = Rs.1,331

Rate of interest (R) = 10% per annum

Formula Used:

The formula for compound interest is:

​$$A = P \left(1 + \frac{R}{100}\right)^{T}$$​​

Solution:

​$$1,331 = 1,000 \left(1 + \frac{10}{100}\right)^{T}\\\ \\1,331 = 1,000 \left(1.1\right)^{T}\\\ \\1.331 = \left(1.1\right)^{T}\\\ \\$$

$$(1.1)^3 = (1.1)^T$$

T = 3 years 

Thus, the time required for Rs.1,000 to become Rs.1,331 at an interest rate of 10% compounded annually is 3 years.