A train crosses a pole in 12 sec, and a bridge of length 170m in 36 sec, Then the speed of the train is?
Show answer & explanation
Correct answer: B
Explanation
The correct answer is option 2 i.e. 25.5 km/h
| Understanding | Application |
| Tricks |
let the length of the train is x m we know speed = distance/time |
| Now |
Since in both case, the speed of the train is constant So x/12 = (x + 170)/36 ⇒ x = (x + 170)/3 ⇒ 3x = x + 170 ⇒ 2x = 170 ⇒ x = 85 |
| Hence |
speed = 85/12 = 85/12 × 18/5 = 25.5 km/h |