Question

a train travels a distance of 20 km per/h with a uniform speed of 60 km per /h it travels another distance of 40km per/h with a uniform speed of 80 km per/h calculate the average speed of the train
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Answer 1

Answer:

total distance=20 +40=60km

Time 1=20/60=1/3

time 2=40/80=1/2

avg.speed=total distance/total time

=60/1/3+1/2

=72km/h

Answer 2

Answer:

total distance =20+40=60

total time

time for 1 case=distance /speed

=20/60

=1/3hr

time for 2 case=

=40/80

=1/2hr

total time =1/3+1/2

=5/6hr

average speed = total distance /total time

=60÷5/6

=60×6/5

=12×6

=72 km/hr