Question

The Average speed of a train running at the rate of 30km/h during the first 100km at 40 km/h during the second 100km at 50km/h during the third 100km is

Answer 1

total distance covered=300 km

total time taken= 100/30 + 100/40 + 100/50
............................ = 47/6

so, Average speed=300/47/6

=38.3 km/hr

Answer 2

time for first is 100/40=5/2hr

2nd is 100/50= 2hr

3rd be X

average speed =total distance /total time

=300/(5/2+2+X)=30

X=11/2

3rd speed =100/(11/2)=200/11