Question

Karan invested a sum of Rs.8400 at 5 % per annum compound interest. He received an amount of Rs.9261 after t years. Find t
1. 1 year
2. 3 years
3. 2 years
4. 5 years

Answer 1

Correct Answer - Option 3 : 2 years

Given

Rate of interest = 5 %

Principal = Rs. 8400

Amount = Rs. 9261

Formula

Amount = Principal [(1 + r %)]^t

Calculation

9261 = 8400[(1 + 5 %)]^t

⇒  (9261/8400) = (105/100)^t

⇒  (441/400) = (21/20)^t

⇒  (21/20)² = (21/20)^t

⇒  t = 2 years