Multiple choice

Braun invested a certain sum of money at $8\%$ per annum simple interest for "$n$" years. At the end of "$n$" years, Braun got back $4$ times his original investment. What is the value of $ n$?

  1. $35.5$
  2. $36.5$
  3. $37.5$
  4. $38.5$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Simple interest formula is I = P * r * n / 100. If the total amount is 4 times the principal, the interest earned is 3 times the principal. So, 3P = P * 8 * n / 100, which simplifies to 3 = 0.08n, so n = 3 / 0.08 = 37.5.

AI explanation

If Braun gets back 4 times his original investment, the simple interest earned equals 3 times the principal. Using the formula Time equals Interest divided by (Principal times Rate), we get Time equals 3 times Principal divided by (Principal times 0.08). The principals cancel out, leaving 3 divided by 0.08, which results in a time of 37.5 years.

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