A sum of money amounts to Rs. 10240 in 2 years at 6% per annum, compounded annually. Find the sum.
Let sum = P
Interest rate = 6% = (20/3) % per annum
Time = 2 years
Now,
Amount (A) = P (1 + R/100)n [Where, P = Present value
R = Annual interest rate
n = Time in years]
∴ A = P[1 + (20/3)/100]2
⇒ 10240 = P [1 + 1/15]2
⇒ 10240 = P [16/15]2
⇒ 10240 = P × 256/225
⇒ P = 10240 × 225/256
⇒ P = 40 × 225
⇒ P = 9000
∴ Sum = Rs.9000