Final answer:
To find Michaela's average speed for the entire trip, we need to calculate the total distance traveled and the total time taken. The average speed can be calculated as (2D) / (D/3 + D/5), which is approximately 3.53 mi/h.
Step-by-step explanation:
To find Michaela's average speed for the entire trip, we need to calculate the total distance traveled and the total time taken.
Let's assume the distance she climbed up the mountain is D. The distance she climbed down is also D since she retraced her steps. The average speed for climbing up is 3 mi/h and the average speed for climbing down is 5 mi/h.
The total distance is 2D and the total time is D/3 + D/5. Therefore, the average speed can be calculated as (2D) / (D/3 + D/5).
Simplifying this expression gives us the average speed as 3.53 mi/h (rounded to the nearest tenth).