A train travel 20km at a uniform speed 60km/1hr and the next 20km at a uniform speed of 80km/1hr calculate its average speed

avgspeed=distance/time

time= 20/60 + 20/80 hrs=1/3 + 1/4 hr
= 7/12 hr

distance=40 km

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yes 68.57 is correct but i want the solution also

To calculate the average speed, you need to find the total distance traveled and the total time taken. In this case, the train is traveling 20km at a speed of 60km/h and another 20km at a speed of 80km/h.

First, let's calculate the time taken for each part of the journey:

Time taken for the first 20km:
Distance = 20km
Speed = 60km/h
Time taken = Distance/Speed = 20km / 60km/h = 1/3 hours

Time taken for the second 20km:
Distance = 20km
Speed = 80km/h
Time taken = Distance/Speed = 20km / 80km/h = 1/4 hours

Now, let's calculate the total distance traveled:

Total distance = 20km + 20km = 40km

Next, let's calculate the total time taken:

Total time taken = (1/3) hours + (1/4) hours = (4/12) hours + (3/12) hours = 7/12 hours

Finally, we can calculate the average speed by dividing the total distance by the total time:

Average speed = Total distance / Total time taken = 40km / (7/12)hours

To divide by a fraction, we multiply by its reciprocal:

Average speed = 40km * (12/7) hours = 480/7 km/h ≈ 68.57 km/h

Therefore, the average speed of the train is approximately 68.57 km/h.

68 . 57