A train runs at the speed of 72 km/hr and crosses a 320 m long platform in 30 seconds. What is the length of the train?

Question: A train runs at the speed of 72 km/hr and crosses a 320 m long platform in 30 seconds. What is the length of the train?

Solution:

Speed = (72 × 1000)/3600 m/sec = 20 m/sec
Time = 30 sec
Let the length of the train be x meters.

Now,
(x + 320)/30 = 20
⇒ x + 320 = 600
⇒ x = 600 - 320
∴ x = 280

∴ The length of the train is 280 meters.