A sum amounts to Rs. 3149.29 in 3 years at compound interest. The sum is?

Let P be the principle and R% per annum be rate
Then, P(1 +R/100)³ = 3149.28 .....(i)
and P(1 + R/100)² = 2916 .....(ii)
on dividing(i) and (ii) we get
∴ (1 + R/100) = 3149.28/2916
⇒ R/100 = 233.28/2916
⇒ R = 233.28/2916 x 100 = 8%
Now, P(1 + 8/100)² = 2916
⇒ P x 27/25 x 27/25 = 2916
∴ P = (2916 x 25 x 25)/(27 x 27)
= Rs. 2500