# What is the Length of Bridge?

A person riding a bike crosses a bridge with a speed of 54 km/h. What is the length of the bridge if he takes 4 min to cross the bridge?

- 3600 m
- 2800 m
- 3500 m
- 4500 m

**Answer: (1) 3600 m**

**Explanation:-**

The speed of a bike = 54 km/h.

Speed in m/sec = 54 x 5/18

= 3 x 5

= 15 m/sec

The distance covered by the bike in 4 min = the length of the bridge.

1 min = 60 sec

Therefore, 4 min = 4 x 60 = 240 sec

The distance covered by the bike in 240 sec = 15 x 240

= 3600 m

The length of the bridge is 3600 m.

Hence, the answer is (1) 3600 m.