Multiple choice

An amount doubles itself at compound interest in 5 years. How many years will it take to make the amount 16 times itself?

  1. 25

  2. 15

  3. 16

  4. 20
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

If an amount doubles in 5 years, it becomes 2^n times in n * 5 years. To reach 16 times, we need 2^4, so it takes 4 * 5 = 20 years.

AI explanation

Using the compound interest formula A equals P times the quantity 1 plus R over 100 raised to the power of n, if the amount doubles in 5 years, then 2 equals 1.15 raised to the power of 5. To become 16 times itself, the amount must double 4 times, since 2 to the power of 4 is 16. Therefore, it will take 4 times 5, which is 20 years.

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