When only the travel time is taken, the average speed of a train is 54 km per hour, but when the stopping time is also taken, the average speed becomes 45 km per hour. For how many minutes per hour does the train stop?

Hi, Let us assume that the travel time is 1 hr, so in 1hr distance traveled is 54 Km.

Let us assume the wait time is 't' hrs

So Total distance traveled with the waiting is = 54 km
Total time taken= t+1 (1 is the 1 hr that the person traveled)

Speed = Distance/ time

Speed = 54/ (t+1)

45= 54/ (t+1)

t= 9/45

9/45 * 60 = 12 mins

Hope this helps!