A car travels the first 120 miles of a trip at an average speed of 40 mph and the remaining 180 miles at an average speed of 60 mph. What is the car's average speed for the entire trip?

✓ Correct Answer: Option B

Time for first part = 120 miles / 40 mph = 3 hours. Time for second part = 180 miles / 60 mph = 3 hours. Total distance = 120 + 180 = 300 miles. Total time = 3 + 3 = 6 hours. Average speed = 300 miles / 6 hours = 50 mph.