Multiple choice

A sum of Rs. 5,000 at compound interest becomes double in 5 years. What will be the amount in 20 years?

  1. Rs. 1,00,000

  2. Rs. 80,000

  3. Rs. 50,000

  4. Rs. 20,000
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Under compound interest, the principal grows by the same factor over equal intervals of time. Since the sum doubles every 5 years, in 20 years it will undergo 4 doubling cycles (20 divided by 5). Therefore, the final amount will be 5,000 * 2^4 = 5,000 * 16 = Rs. 80,000.

AI explanation

Since the sum doubles in 5 years, it becomes four times in 10 years, eight times in 15 years, and sixteen times in 20 years. The final amount is the original sum of Rs. 5,000 multiplied by 16. The total amount after 20 years is Rs. 80,000.

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