Question: If a sum of money doubles itself in 5 years at simple interest, what will be the rate of interest?
Options:
Correct Answer: 10%
Solution:
Using the formula for simple interest, we know that the interest earned is equal to the principal. Therefore, if the principal doubles in 5 years, the rate of interest can be calculated as (100 * Interest) / (Principal * Time) = (100 * Principal) / (Principal * 5) = 20%. Thus, the rate of interest is 20%.