Multiple choice

In what time will a sum become three times itself at 20% per annum, at simple interest?

  1. 8 years

  2. 10 years

  3. 15 years

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

Let the principal be P. The amount becomes 3P, so the simple interest earned is 2P. Using the formula SI = (P * R * T) / 100, we have 2P = (P * 20 * T) / 100. Solving for T gives T = 200 / 20 = 10 years.

AI explanation

To become three times itself at simple interest, the interest earned must be twice the principal. Let the principal be P, so the required interest is 2P. Using the simple interest formula, Time equals Interest multiplied by 100 divided by the product of Principal and Rate, giving 2P times 100 divided by P times 20. Solving this gives 10 years.

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