Task: Question Answering
Input (English): Problem: a can finish a work in 18 days and b can do the same work in half the time taken by a . then , working together what part of the same work they can finish in a day ? 
Options: a ) 1 / 2 , b ) 1 / 3 , c ) 1 / 6 , d ) 2 / 5 , e ) 2 / 9
Output (English): c