A sum becomes Rs. 6615 in 2 years and Rs. 6945.75 in 3 years at compound interest. Find the sum. MCQ with Answer and Explanation

Explanation:
The sum doubles (2^1) in 20 years. It will become 4 (2^2) times in 2 * 20 = 40 years.

Explanation:
Rate = (5324/4840 − 1) × 100 = (1.1 − 1) × 100 = 10%.

Explanation:
Difference for 3 years = P * (R/100)^2 * (3 + R/100) => 620 = P * (10/100)^2 * (3 + 10/100) => 620 = P * (1/100) * (3.1) => 620 = P * 0.031 => P = 620 / 0.031 = Rs. 20000.