At what rate percent per annum will the simple interest on a sum of money be 3/5 of the amount in 10 years? Choose the correct answer: A) 6 % B) 7 % C) 9 % D) 3 % E) 1 %

Rationale: "let sum = x . then , s . i . = 2 x / 5 , time = 10 years . rate = ( 100 * 3 x ) / ( x * 5 * 10 ) = 6 % answer : a"
Answer: A