Question

On a 60 km track a train travels the first 30 km/h how fast must tra vel the next 30 kmso asto avg 40km/h

Answer 1

Average speed= total distance/total time taken

So time. Comes out to be 1.5 hrs.

1 hrs was travelled at 30kmph to cever 30km.

So remainder of 30 km have to be covered at x speed to cover in .5hrs.

Speed=distance/time

Speed=30/.5

Speed=60 km/hr

i hope it will help you 

regards