On a sum of money, the S.I. for 2 years is $600, while the C.I. is $630, the rate of interest being the same in both the cases. The rate of interest is?	Choose the correct choice from the following choices
A) 8 %
B) 10 %
C) 12 %
D) 14 %
E) 16 %

Rationale: "difference in c . i . and s . i for 2 years = $ 630 - $ 600 = $ 30 s . i for one year = $ 300 s . i . on $ 300 for 1 year = $ 30 rate = ( 100 * 30 ) / ( 300 ) = 10 % the answer is b ."
Answer: B