Question

3. A train travels 20 km at a uniform speed of 60 km/h and the next 20 km at a uniform speed of 80km/h. Calculate its average speed.​

Answer 1

Given,

Distance traveled = 20 km

Speed = 60 km/h

So, timetaken=DistanceSpeed=2060=13h

For the next journey

Distance traveled = 20 km

Speed = 80 km/h

So, timetaken=DistanceSpeed=2080=14h

Now,

Total distance traveled = 20 + 20 = 40 km

Total time taken = 13+14=712

We know,

Averagespeed=TotaldistancetraveledTotaltimetaken=40712=68.5 km/h

Hence the average speed of the train is 68.5 km/h