Question

the distance between two station is 120 km A train travels the first 30 km at uniform speed of 30 km per hour how fast must be train travels the next 90 km so as the average 60 km per hour for the entire trip​

Answer 1

Distance between station=120km

For first 30km,

speed=30km/hr

Distance=30km

Time taken=distance/speed=30/30 hr=1 hr

Remaining distance=90 km

Average speed needed=60km/hr

Total time taken by the train if traveled by the average speed=120/60 hr=2 hr

Therefore, the train must be covering the remaining 90 km in 2-1=1 hr so as to make an average of 60 km/hr.

Hence,

speed for 90 km=90km/hr.