Task: Question Answering
Input (English): Problem: the time it took car p to travel 600 miles was 2 hours less than the time it took car r to travel the same distance . if car p ’ s average speed was 10 miles per hour greater than that of car r , what was car r ’ s average speed , in miles per hour ? 
Options: a ) 40 , b ) 50 , c ) 60 , d ) 70 , e ) 80
Output (English): b