Answer:
88.9 km/h
Step-by-step explanation:
Average speed = total distance / total time
The total distance is:
d = 160 km + 160 km
d = 320 km
The total time is:
t = (160 km) / (80 km/h) + (160 km) / (100 km/h)
t = 2 h + 1.6 h
t = 3.6 h
Therefore, the average speed is:
s = 320 km / 3.6 h
s = 88.9 km/h