Answer:
49.45mph
Step-by-step explanation
3 hours 28 min needs to be changed to decimal form so to do that we take 28/60 to get .466 so the new time for the second part of the trip is 3.466 hours.
from their you can add the distances of each part of the trip and divide that by the total time to get your average speed of 49.45mph
((rate1 x time1) + (rate2 x time2)) / (time1 + time2)
((37 x 2.1) + (57 x 3.466)) / (2.1 + 3.466)
(77.7 + 197.562)/ (5.566)
49.45mph
