Question

A train 300 m long train passes a pole in 15 seconds and crosses another train of the same length travelling in the opposite direction in 8 seconds. Calculate the speed of the second train in km / h.
1. 200 km/h
2. 198 km/h
3. 190 km/h
4. 222 km/h
5. 132 km/h

Answer 1

Correct Answer - Option 2 : 198 km/h

Given:

Length of train = 300 m

Time is taken by train to pass a pole = 15 seconds

Time is taken to cross another train of the same length = 8 seconds

Formula Used:

Speed = Distance/Time

Calculations:

Speed of the 1st train = 300/15 = 20 m/s

Let the speed of 2nd train be x

Relative speed = (20 + x) m/s

Length of 1st train + length of 2nd train = 300 + 300 = 600 m

In the second scenario the equation is

⇒ 600/(20 + x) = 8

⇒ 600 = 160 + 8x

⇒ 600 - 160 = 8x

⇒ 440 = 8x

⇒ x = 55 m/s

⇒ Speed of the train = 55 × (18/5) = 198 km/h.

∴ The speed of the second train is 198 km/h.