Simple interest on a certain sum at a certain annual rate of interest is 1/25 of the sum. If the numbers representing rate percent and time in years be equal, then the rate of interest is: Choose the correct answer
A) 5 %
B) 2 %
C) 6 %
D) 8 %
E) 3 %
Explanation :   Let sum = x. Then, S.I. = x/25   Let rate = R% and time = R years.   [x * R * R / 100] = x / 25? R^2 = 100/25= 
<gadget id="calculator">100/25</gadget>
<output>4</output>
4   R= 2   Hence, rate of interest = 2 %.   Answer : 2 %
<result>B</result>
Simple interest on a certain sum at a certain annual rate of interest is 1/25 of the sum. If the numbers representing rate percent and time in years be equal, then the rate of interest is: