# When does the train clear the platform?: visual | SwaVid

A 180 m train travels at 54 km/h. How many seconds does it take to completely pass a 270 m platform? See the complete step-by-step solution.

Canonical: https://www.swavid.com/puzzles/train-platform

Source: https://www.swavid.com/puzzles/train-platform

# When does the train clear the platform?

## 30 seconds.

### Convert the speed

### Find the total distance

### Divide distance by speed

SwaVid visual puzzle

A 180 m train travels at 54 km/h. How many seconds does it take to completely pass a 270 m platform?

Detailed solution

To clear the platform completely, the train must travel the platform's length plus its own length.

Change km/h into m/s by multiplying by 1000/3600.

The front of the train must reach the far end of the platform, then the whole train must follow.

Time is distance over speed.

Using only the platform's 270 m gives 18 s, which is when the front reaches the end, not when the last carriage clears it.

- 1 Convert the speed Change km/h into m/s by multiplying by 1000/3600. 54 × 5/18 = 15 m/s
- 2 Find the total distance The front of the train must reach the far end of the platform, then the whole train must follow. 180 + 270 = 450 m
- 3 Divide distance by speed Time is distance over speed. 450 ÷ 15 = 30 s

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