Task: Question Answering
Input (English): Problem: working together , printer a and printer b would finish the task in 30 minutes . printer a alone would finish the task in 50 minutes . how many pages does the task contain if printer b prints 3 pages a minute more than printer a ? 
Options: a ) 200 , b ) 400 , c ) 600 , d ) 800 , e ) 900
Output (English): b