Subject: mathqa
Question: jerry travels 8 miles at an average speed of 40 miles per hour , stops for 14 minutes , and then travels another 20 miles at an average speed of 60 miles per hour . what is jerry ’ s average speed , in miles per hour , for this trip ?
Option: 
A: 36
B: 50
C: 52.5
D: 42.5
Answer: A