On a 120 km track, a train travels the first 30 km at a uniform speed of 300 km/h. Calculate the speed with which the train should move rest of the track so as to get the average speed of 60 km/h for the entire trip?

The speed with which the train should move rest of the track so as to get the average speed of 60 km/h for the entire trip is 47.4 km/hr