A train passes a station platform in 36 seconds and a man standing on the platform in 20 seconds. If the speed of the train is 54 km/hr, what is the length of the platform?

Given Data

• Train speed = 54 km/hr
• Time to pass a man = 20 s
• Time to pass a station platform = 36 s
• Required: platform length

Step 1: Convert speed and find train length54 km/hr = 54 × (5/18) = 15 m/sTrain length L = 15 × 20 = 300 m

Step 2: Use platform-crossing timeTotal distance during platform crossing = 15 × 36 = 540 mPlatform length = 540 − 300 = 240 m

Checks & Common Pitfalls

• Passing a man uses only the train length to obtain speed/length.
• For a platform, add the platform length to the train length.

Final AnswerThe platform length is 240 m.