Task: Question Answering
Input (English): Problem: machine a produces 100 parts thrice as fast as machine b does . machine b produces 100 parts in 30 minutes . if each machine produces parts at a constant rate , how many parts does machine a produce in 6 minutes ? 
Options: a ) 20 , b ) 80 , c ) 40 , d ) 60 , e ) 50
Output (English): d