Task: Question Answering
Input (English): Problem: john traveled 80 % of the way from yellow - town to green - fields by train at an average speed of 80 miles per hour . the rest of the way john traveled by car at an average speed of v miles per hour . if the average speed for the entire trip was 50 miles per hour , what is v in miles per hour ? 
Options: a ) 20 , b ) 40 , c ) 50 , d ) 55 , e ) 70
Output (English): a