Question

A train travels at a speed of 50 m/s. How far will it travel in 20 seconds?

Answer 1

Let the distance between A and B be x km.

Then time for A to B, say t1= x/20

And time for B to A, say t2= x/30.

Hence total time, say T=t1+t2 =x/12.

In going from A to B and then returning total distance = 2x.

Hence avg speed= 2x÷x/12= 24 km/h.