A 300 metre long train crosses a platform in 39 seconds while it crosses a signal pole in 18 seconds. What is the length of the platform?

Given Data

• Train length = 300 m
• Time to pass a pole = 18 s
• Time to pass a platform = 39 s
• Required: platform length

Step 1: Find train speed from pole crossing
Speed v = distance ÷ time = 300 ÷ 18 = 16.6667 m/s = 50/3 m/s

Step 2: Use platform crossing to get total distance
Total distance = v × 39 = (50/3) × 39 = 650 mPlatform length = total distance − train length = 650 − 300 = 350 m

Checks & Common Pitfalls

• For a pole, use only train length to compute speed.
• For a platform, add platform length to train length.

Final Answer
The platform length is 350 m.