Final answer:
To find Dana's average speed over the two runs, add up the distances and times for both runs. Then divide the total distance by the total time to calculate the average speed.
Step-by-step explanation:
To find Dana's average speed over the two runs, we need to calculate the total distance and the total time taken.
For Monday's run, Dana ran 3 km in 17 minutes, which gives a speed of 3 km/17 min.
For Friday's run, Dana ran 9 km in 50 minutes, which gives a speed of 9 km/50 min.
To find the average speed, we add up the distances and the times for both runs. In this case, the total distance is 3 km + 9 km = 12 km, and the total time is 17 min + 50 min = 67 min.
To convert the total time to hours, we divide by 60: 67 min ÷ 60 = 1.12 hours.
Finally, we calculate the average speed by dividing the total distance by the total time: 12 km ÷ 1.12 hours = 10.71 km/h.
Therefore, Dana's average speed over the two runs is 10.71 km/h.