Multiple choice

In how much time, at simple interest, will a sum of money double itself at 20%?

  1. 4 years

  2. 5 years

  3. 6 years

  4. 8 years
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

For simple interest, to double the money, the interest earned must equal the principal. SI = P * R * T / 100. P = P * 20 * T / 100. 1 = 20 * T / 100. T = 5 years.

AI explanation

To double a sum at simple interest, the interest earned must equal the principal, meaning P equals (P * R * T) / 100. Cancelling P from both sides leaves 1 equal to (20 * T) / 100. Solving for T gives T equals 5 years.

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