Task: Question Answering
Input (English): Problem: the ages of 2 persons differ by 18 years . if 12 years ago the elder one be 6 times as old as the younger one , find the present age of elder person . 
Options: a ) 33.6 , b ) 47 , c ) 50.4 , d ) 52.4 , e ) 47.9
Output (English): a