Detailed Instructions: In this task, you need to answer the given multiple-choice question on the physics. Classify your answers into 'a', 'b', 'c', 'd', and 'e'.
Q: Problem: working together , printer a and printer b would finish the task in 24 minutes . printer a alone would finish the task in 60 minutes . how many pages does the task contain if printer b prints 7 pages a minute more than printer a ? 
Options: a ) 600 , b ) 840 , c ) 1000 , d ) 1200 , e ) 1500
A:
b