Priya borrowed a certain sum at the rate of 12% per annum. If she paid Rs 10176 at the end of 2 years as interest compounded annually. What was the sum she borrowed?

Rs 40000

Formula used-

Amount = P$(1 \;+\; \frac{R}{100})^t$

Compound Interest = Amount - Principal

Here, Compound interest = Rs 10176, R = 12%, t = 2 years 

    10176 =  P$(1 \;+\; \frac{12}{100})^2$ - P

⇒ 10176 = P[$(\frac{28}{25})^2 - 1$]

⇒ 10176 = P[$\frac{784}{625}$ - 1]

⇒ 10176 = P[$\frac{159}{625}$]

⇒     P    = $\frac{10176 \times 625}{159}$  

⇒     P    = 40000

Thus, Sum borrowed is Rs 40000