Task: Question Answering
Input (English): Problem: the ratio of the present age of sandy to that of molly is 9 : 2 . eight years from now , the ratio of the ages of sandy to molly will be 5 : 2 . what was sandy ' s age 6 years ago ? 
Options: a ) 18 , b ) 21 , c ) 24 , d ) 27 , e ) 30
Output (English): b