Multiple choice

In how many years will a certain sum becomes five times itself at 20% per annum simple interest?

  1. 20

  2. 18

  3. 16

  4. 12
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Simple Interest formula: SI = P*R*T/100. Amount = P + SI = 5P, so SI = 4P. 4P = P * 20 * T / 100 => 4 = 0.2 * T => T = 20.

AI explanation

If a sum becomes five times itself, the simple interest earned is 4 times the principal (4P). Using the simple interest formula SI = (P * R * T) / 100, we substitute the known values to get 4P = (P * 20 * T) / 100. Dividing both sides by P yields 4 = 20T / 100. Solving for T gives T = 400 / 20, which equals 20 years.

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