At what rate percent of simple interest will a sum of money double itself in 66 years? Choose the correct choice.
A) 6.54 %  B) 4.54 %  C) 1.51 %  D) 1.94 %  E) 5.54 %
Let sum = x. Then, S.I. = x.   Rate = (100 * S.I.) / (P * T) = (100 * x) / (x * 66)   = 100/66 = 1.51 %   ANSWER:1.51 %
<result>C</result>
At what rate percent of simple interest will a sum of money double itself in 66 years?