Subject: mathqa
Question: 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 65 miles per hour , what is v in miles per hour ?
Option: 
A: 70
B: 40
C: 55
D: 30
Answer: C