Answer:
130 km/hr
Explanation:
Average Speed = Total Distance / Total Time.
Let us just make up 2 distances from a time
A: 55 km/hour for 2 hours = 110 km
B: 75 km/hour for 2 hours = 150 km
Total Distance = 260 km
Total Time = 2 hours.
Average Speed = 260 / 2 = 130 km/hr
Now let's try it again. If we get a different answer, then the problem is unanswerable.
A: 55 km/hr for 3 hours = 165 km
B: 75 km/hr for 3 hours = 225 km
Total distance = 390 km
Total time = 3 hours
Average speed = 390 / 3 = 130 which is the same answer we got before.