Multiple choice

A certain sum becomes k times in 5 years at compound interest. How many times will it become in 30 years?

  1. 5k

  2. 6k

  3. k6

  4. k5
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Compound interest formula: A = P(1+r)^t. If it becomes k times in 5 years, (1+r)^5 = k. In 30 years, it becomes P(1+r)^30 = P((1+r)^5)^6 = P*k^6.

AI explanation

Using the compound interest formula, the amount becomes the principal multiplied by (1 plus the rate) raised to the power of 5, which is given as k times the principal. Therefore, the quantity (1 plus the rate) raised to the fifth power equals k. To find the multiplier for 30 years, we raise this quantity to the power of 6, meaning the sum will become k raised to the power of 6, written as k6.

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