Correct Answer - Option 1 : 350 m

**Given:**

Length of train = 150m

Speed of train = 60 km/h

Time to cross the bridge = 30 sec

**Concept Used:**

1 km/hr = 5/18 m/sec

Distance = Speed × Time

**Calculation:**

Speed of train = 60kmph = 60 × 5/18 = 50/3 m/sec

Let length of bridge be a m.

Then,

⇒ 50/3 = (a + 150)/30

⇒ 500 = a + 150

⇒ a = 350

**∴ Length of bridge is 350m.**

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Time taken to cross a platform by a train = (length of platform + length of train)/speed of train