# What was his average speed of the journey ?

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A man drive his car to the office at 20 km/hr.
After reaching office, he realize that its a new year holiday so he went back home at a speed of 30 km/hr.

Discounting the time spent in the stoppage what was his average speed of the journey ?

posted Jun 3, 2014

we can calculate it using Harmonic Mean
average speed = (2 x 20 x 30) / (20 + 30) = 1200 / 50 =24.

let distance between home and office is 20 km
then total distance =20+20=40km
total time = 1+2/3=5/3 hours
average speed =total distance/total time
=40/(5/3)
=24km/hr

average speed of car=(2*20*30)/50
=24 km/hr

v=s/t => v = 40km/(5/3)h => v = 24km/h

answer Jun 23, 2019 by anonymous

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