a car crosses the street ABC. the segment AB = average speed of 60km / h for 2 hours, the length BC = average speed of 90km / h for 1 h. the average speed of car travel in AC is? the route is a straight line
How can it take three hours to cross a strret? It sounds to me like the car is traveling ALONG ABC, not across it.
To find the average speed of the car during the entire journey from A to C, you need to calculate the total distance traveled and the total time taken.
To calculate the total distance traveled, you need to add the distances of segments AB (AB = average speed of 60 km/h for 2 hours) and BC (BC = average speed of 90 km/h for 1 hour).
Distance AB = speed * time = 60 km/h * 2 hours = 120 km
Distance BC = speed * time = 90 km/h * 1 hour = 90 km
Total distance = Distance AB + Distance BC = 120 km + 90 km = 210 km
To calculate the total time taken, you need to add the time taken for segments AB and BC.
Total time = Time AB + Time BC = 2 hours + 1 hour = 3 hours
Finally, to find the average speed of the car during the entire journey, you divide the total distance traveled by the total time taken.
Average speed = Total distance / Total time = 210 km / 3 hours ≈ 70 km/h
Therefore, the average speed of the car during the journey from A to C is approximately 70 km/h.