Correct Answer - Option 3 : 160 metres

**Given **

Length of first train = 480 meters

Speed of train = 36 km/hr

**Formula Used **

Distance = Time × Speed

**Calculation **

Let the length of bridge be x

Distance = length of train + length of bridge

⇒ x + 480 = 36 ×(5/18) × 64

⇒ x = 640 - 480 = 160 metres

**∴ The length of bridge is 160 metres**