Question

Two trains are moving in the same directions at speed of 43 km/h and 51 km/h respectively. The time taken by the faster train to cross a man sitting in the slower train is 72 seconds. What is the length (in metres) of the faster train?

1. 160
2. 338.4
3. 470
4. 940

Answer 1

Correct Answer - Option 1 : 160

Given: The speed of 2 trains = 43 km/hr and 51 km/hr

⇒ Relative velocity of one train w.r.t. another while going in same direction = (51 - 43)km/hr = 8 km/hr

⇒ Relative velocity in m/s = 8 × (5/18) m/s

⇒ Distance covered by the faster train in 72 sec = 8 × (5/18) × 72 = 160

Since, this is the distance covered in crossing the man = length of the faster train

Hence, the length of faster train = 160 m

∴ the correct option is 1)