Question

A train running at 72 km/h crosses a pole in 12 seconds. How much time (in seconds) will it take to cross a bridge 360 m long?
1. 30
2. 40
3. 60
4. 75

Answer 1

Correct Answer - Option 1 : 30

Given:

Speed = 72 km/h

Time = 12 sec

Distance = 360 m

Formula used:

Time = Distance/Speed

Calculation:

Speed = 72 × 5/18

⇒ 20 m/s

Distance = Length = (20 × 12) m

⇒ 240 m

Now,

Time = Distance/Speed

⇒ (360 + 240)/20

⇒ 600/20

⇒ 30 sec

∴ Required time is 30 sec