Answer:
5km/h
Explanation:
The equation for average speed is
Vavg = Δd/Δt
where Δd is distance and Δt is time
from what's given, we know she travelled 15km in total and the trip took 3 hours in total. We can now plug in the values into the equation
Vavg = 15/3
Vavg = 5km/h