Question

A hundred metre long train crosses a man travelling at 5 km per hour in opposite direction and 7.2 seconds then the velocity of trainers

Answer 1

Let the speed of the train  = x


Since the man and the train are moving in opposite direction'

The relative speed = (5 + x) km/h


Time taken to overtake the man is the time required to cover a distance of 100m (the length of the train)


100 m = 0.1km and 7.2 seconds = 7.2/3600 = 0.002 hours





Time = Distance/Speed


Time = 0.1/(x + 5) = 0.002


 x +5 = 0.1/0.002 = 50



x = 50 -5

x = 45



The speed of the train =  45km/h

Answer 2

Answer:

Explanation:

Let the speed of the train = x

Since the man and the train are moving in opposite direction'

The relative speed = (5 + x) km/h

Time taken to overtake the man is the time required to cover a distance of 100m (the length of the train)

100 m = 0.1km and 7.2 seconds = 7.2/3600 = 0.002 hours

Time = Distance/Speed

Time = 0.1/(x + 5) = 0.002

x +5 = 0.1/0.002 = 50

x = 50 -5

x = 45

The speed of the train = 45km/h