Correct Answer - Option 1 : 13 seconds

**Given:**

Speed of train = 108 km/h

T = 6 seconds

L of platform = 210 m

**Formula used:**

Speed = Distance/Time

m/s = 5/18 km/hr

**Calculation:**

Converting speed of train from km/h to m/s = 108 × 5/18

⇒ speed = 30 m/s

⇒ Length of train = 30 × 6

⇒ Length of train = 180 m

⇒ Time taken to cross platform of 210 m = (210 + 180)/30

⇒ Time taken to cross platform of 390 m = 13 seconds

**∴**** time taken to cross platform of 210 m is 13 seconds**