Question

'A train 400m long is travelling at a speed of 72 Km/hr. How
long will it take to cross a lamp post?​

Answer 1

Step-by-step explanation:

Short Answer: 20 seconds

Long Answer:

First Convert 72 km/hr to m/s

72×1000/(60×60) = 20 m/s

Time to cover 200 m bridge = 200 m/(20 m/s) => 10 s

Since length of the train is 400 m, the bridge can only hold half the length of the train. So the other half will take another 10 s.

So, 10 s + 10 s = 20 s

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