Task: Question Answering
Input (English): Problem: while working alone at their constant rates , computer x can process 240 files in 12 hours , and computer y can process 240 files in 6 hours . if all files processed by these computers are the same size , how many hours would it take the two computers , working at the same time at their respective constant rates , to process a total of 240 files ? 
Options: a ) 3 , b ) 3.5 , c ) 4 , d ) 4.5 , e ) 5
Output (English): c