Question

A train is travelling at a speed of 45km/hr.If it crosses a signal pole in 18 seconds, how much time will it take to cross a 125 m long platform

Answer 1

speed of train = 45km/h = 45 × 1000/3600 m/s
= 45 × 5/18 = 12.5 m/s

a/c to question,
train crosses a signal pole in 18 seconds.
so, length of train = distance travelled by train in 18 seconds
= speed of train × time taken
= 12.5 × 18 = 225 m

hence, length of train = 225m

now, time taken to cross a 125m long platform = (length of platform + length of train)/speed of train
= (125 + 225)/12.5
= 350/12.5
= 700/25
= 28 seconds .

hence, time taken to cross a 125 long platform is 28 seconds.

Answer 2

Speed of the Train = 45 km/hr = 12.5 m/s.

Time taken to cross a single pole = 18 seconds.

Therefore, Length of the Train = 12.5 × 18 = 225 m.

Now, for Platform, Total distance to be covered = length of the train + length of the platform

= 225 + 125

= 350 m.

Now, Time taken to cross the Platform = Total length/Speed of the train

= 350/12.5

= 28  seconds.

Hence, the time taken by the train to cross the Platform is 28 seconds.

Hope it helps.