Task: Question Answering
Input (English): Problem: the ages of two persons differ by 16 years . if 6 years agao , the elder one be 3 times as old as the younger one , find their present ages . 
Options: a ) 20 years . , b ) 30 years . , c ) 40 years . , d ) 50 years . , e ) 60 years .
Output (English): b