Multiple choice

A sum placed at Simple Interest triples in 6 years. In how many years will it become 9 times?

  1. 24

  2. 18

  3. 12

  4. 9
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A Correct answer
Explanation

Simple interest: Amount = P(1 + RT). Triples in 6 years: 3P = P(1 + 6R) -> 2 = 6R -> R = 1/3. For 9 times: 9P = P(1 + T/3) -> 8 = T/3 -> T = 24 years.

AI explanation

If a sum triples in 6 years at simple interest, the interest earned equals twice the principal, meaning the interest for one principal amount takes 3 years. To become 9 times the original sum, the total interest must equal 8 times the principal. Multiplying the 3 years needed for each single unit of principal by 8 gives a total of 24 years.

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