Jennifer travels first 4 hours of her journey at a speed of 80 miles/hr and…
2025
Jennifer travels first 4 hours of her journey at a speed of 80 miles/hr and the remaining distance in 6 hours at a speed of 30 miles/hr. What is her average speed in miles/hr?
- A.
50 miles / hr
- B.
60 miles / hr
- C.
75 miles / hr
- D.
92 miles / hr
Attempted by 9 students.
Show answer & explanation
Correct answer: A
Step-by-Step Solution
Average speed is defined as the total distance traveled divided by the total time taken for the entire journey. It is not simply the average of the two speeds.
Calculate the distance for the first part of the journey:
Speed = 80 miles/hr, Time = 4 hours.
Distance 1 = Speed * Time = 80 * 4 = 320 miles.
Calculate the distance for the second part of the journey:
Speed = 30 miles/hr, Time = 6 hours.
Distance 2 = Speed * Time = 30 * 6 = 180 miles.
Calculate the total distance and total time:
Total Distance = Distance 1 + Distance 2 = 320 + 180 = 500 miles.
Total Time = Time 1 + Time 2 = 4 + 6 = 10 hours.
Calculate Average Speed:
Average Speed = Total Distance / Total Time
Average Speed = 500 miles / 10 hours = 50 miles/hr.