A car drives 40 miles on local roads at 20 mph, and 180 miles on the highway at 60 mph, what is the average speed of the entire trip? Choose the correct answer:
A) 36 mph
B) 40 mph
C) 44 mph
D) 52 mph
E) 58 mph
Explanations   1) In phase #1 of the trip, the car traveled 40 mi at 20 mph. That time of this phase was:   time = distance/rate = (40 mi)/(20 mph) = 2 hr   In phase #2 of the trip, the car traveled 180 mi at 60 mph. That time of this phase was:   time = distance/rate = (180 mi)/(60 mph) = 3 hr   The total distance of the trip = 40 mi + 180 mi = 220 mi   The total time of the trip = 2 hr + 3 hr = 5 hr   The average speed of trip is given by   speed = distance/time = (220 mi)/(5 hr) = 44 mph   Answer: 44 mph.
<result>C</result>
A car drives 40 miles on local roads at 20 mph, and 180 miles on the highway at 60 mph, what is the average speed of the entire trip?