A train travels between two stations x and y. While going from x to y, its average speed is 72 km per hour, and while coming back from y to x, its average speed is 63 km per hour. Find the average speed of the train during the whole journey
Answers
Answer: 67.2 km/hr
Step-by-step explanation:
As the distance d travelled during both the journeys is same, the average speed for the entire journey can be given by the formula (2×v1×v2)/(v1 +v2) where v1 and v2 are the different speeds during the journey.. Here v1 is 72km/hr and v2 is 63km/hr. So (2*72*63)/(72+63)
= 67.2km/hr
Answer:
67.2Km
Step-by-step explanation:
Average speed = Total distance/Total time
Now, let the distance between X and Y be 'a' m. As the distance will not change during the journey from the two points. Therefore, total distance covered = 2a km.
Now let the total time taken for the journey be = t hr
So,
Avg Speed = 2a/t
We know that,
Speed = distance/time
Case 1, from X to Y
Time = distance/speed
t = x/72 hr
Case 2, from Y to X
Time = distance/speed
t = x/63 hr
Therefore, total time taken
= x/72 + x/63
=7x + 8x/504
= 15x/504
=5x168
Now using equation 1,
Avg speed = = 2x/5x/168
= 2x × 168/5x
= 67.2 Km/hr
Therefore, its average speed throughout the journey was 67.2 Km/h