If in 13 years fixed sum doubles at simple interest, what will be the interest rate per year? (correct to two decimal places)
Show answer & explanation
Correct answer: A
Explanation
The correct answer is Option 1 i.e. 7.69%
If the sum doubles then after 13 years principal should become equal to interest.
Let the principal be 'P' with the rate of interest 'r'.
⇒ P = (P × r × 13)/100
⇒ r = 100/13
⇒ r = 7.69%