Task: Question Answering
Input (English): Problem: when working alone , painter w can paint a room in 2 hours , and working alone , painter x can paint the same room in z hours . when the two painters work together and independently , they can paint the room in 3 / 4 of an hour . what is the value of z ? 
Options: a ) 3 / 4 , b ) 1 [ 1 / 5 ] , c ) 1 [ 2 / 5 ] , d ) 1 [ 3 / 4 ] , e ) 2
Output (English): b