Question

A body travels 50km at an average speed of 60km/hr and return at an average speed of 80km/hr . Find the average speed of the whole journey

Answer 1

Answer:

68.57 km/hr. (approx)

Explanation:

let the time be t1 to travel to the point and time to return be t1. Then,

distance travelled in first half = 50 km

distance travelled in second half = 50 km

First Half:

50km/t1 = 60km/hr

OR t1 = 50/60 = 5/6hr

Second Half:

50km/t2 = 80km/hr

OR t2 = 50/80 = 5/8hr

Overall distance:

50+50 = 100km

Overall time:

t1+t2 = 5/6 + 5/8 = 35/24

Average Speed :

(100km*24)/35 = 480/7 = 68.57 km/hr. (approx)

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