Multiple choice

If a sum of money doubles itself in 16 years at SI, then the rate of interest per annum is

  1. 25%

  2. 12.5%

  3. 6.25%

  4. 20%
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Simple Interest (SI) = P * R * T / 100. If the sum doubles, SI = P. So P = P * R * 16 / 100. 1 = 16R / 100, R = 100 / 16 = 6.25%.

AI explanation

If a sum doubles in 16 years, the simple interest earned is exactly equal to the principal, meaning P times R times 16 divided by 100 equals P. Simplifying this equation gives R equals 100 divided by 16, which results in a rate of 6.25% per annum.

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