Simple interest on a certain sum at a certain annual rate of interest is 1/9 of the sum. If the numbers representing rate percent and time in years be equal, then the rate of interest is:	Choose the correct choice from the following choices
A) 5  B) 8  C) 3 1/3  D) 2 2/3  E) None
Sol.   Let sum = x. Then, S.I. = x/9   Let rate = R% and time = R years.   ∴ [x * R * R / 100] = x / 9 ↔ R’ = 100/9 ⇔ R = 10/3 = 3 1/3.   Hence, time = 3 1/3 %.   Answer 3 1/3
<result>C</result>
Simple interest on a certain sum at a certain annual rate of interest is 1/9 of the sum. If the numbers representing rate percent and time in years be equal, then the rate of interest is: