Task: Question Answering
Input (English): Problem: pipe a can fill a pool in 12 hours at a constant rate . if pipe a does the job for 8 hours and pipe b does the rest of the job , which works at 1 / 3 constant rate of pipe a . how long will it take for pipe b alone to do the rest of the job ? 
Options: a ) 12 hrs , b ) 6 hrs , c ) 8 hrs , d ) 10 hrs , e ) 24 hrs
Output (English): a