Multiple choice

A sum of money invested at compound interest doubles itself in six years. In how many years will it become 64 times itself at the same rate of compound interest?

  1. 30

  2. 36

  3. 42

  4. 48
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

If a sum doubles in 6 years, it becomes 2^n times in 6*n years. To become 64 times, 2^n = 64, so n = 6. Total time = 6 * 6 = 36 years.

AI explanation

Since the sum doubles in 6 years, its value becomes 2 times itself. To become 64 times itself, it must undergo 6 consecutive doublings, because 2^6 equals 64. Therefore, multiplying 6 years by 6 gives the total time of 36 years.

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