On a sum of money, the S.I. for 2 years is $660, while the C.I. is $693, the rate of interest being the same in both the cases. The rate of interest is?  Choose the correct choice
A) 10 % B) 32 % C) 72 % D) 14 % E) 82 %

Rationale: "difference in c . i . and s . i for 2 years = $ 693 - $ 660 = $ 33 s . i for one year = $ 330 s . i . on $ 330 for 1 year = $ 33 rate = ( 100 * 33 ) / ( 330 ) = 10 % the answer is a ."
Answer: A