Question

A train moves from station A to station B with speed 30 km/hr and comes back with speed 40 km/hr calculate average speed of train

Answer 1

Given that, A train moves from station A to station B with speed 30 km/hr and comes back with speed 40 km/hr.

We have to find the average speed of the train.

Let the distance covered by train be x.

Therefore, the total distance covered by train is (x + x) 2x km.

Speed = Distance/Time

Time = Distance/Speed

For station A:

Time (t1) = x/30

For station B:

Time (t2) = x/40

Average speed = (Total distance)/(Total time)

= (2x)/(t1 + t2)

= (2x)/(x/30 + x/40)

= (2x)/[(3x + 4x)/120]

= (2x)/(7x/120)

= (2x × 120)/(7x)

= 2 × 17.14

= 34.28 km/hr