At what rate percent per annum will the simple interest on a sum of money be 1/5 of the amount in 10 years? Choose the correct answer:
A) 2 %
B) 7 %
C) 9 %
D) 3 %
E) 1 %

Rationale: "let sum = x . then , s . i . = x / 5 , time = 10 years . rate = ( 100 * x ) / ( x * 5 * 10 ) = 2 % answer : a"
Answer: A