At what rate percent per annum will the simple interest on a sum of money be 2/5 of the amount in 10 years?	Choose the correct answer:
A) 4% B) 7% C) 9% D) 3% E) 1%
Let sum = x. Then, S.I. = 2x/5, Time   = 10 years.   Rate = (100 * 2x) / (x * 5 * 10)   = 4%   4%nswer: 4%
<result>A</result>
At what rate percent per annum will the simple interest on a sum of money be 2/5 of the amount in 10 years?