Question

a train travels the first 30 kilometres of 120 km with uniform speed of 30 km per hour. what should be the average speed of the train to cover the remaining distance off the track so that its average speed of 60 km per hour for the entire trip​

Answer 1

Answer:

90 km/ hr

Explanation:

Average speed=Total distance Total time taken

Vav=tdort=Vavd

For 120 km,

t=60 km/hr120 km=2 hr ......(i)

For 1st 30 km,

t1=30 km/hr30 km=1 hr

For remaining 90 km,

t2=t−t1=2−1=1 hr

speed=timedistance or v2=t2d2=190=90 km/hr