Question

A train moving at a speed of 72 kmph of length 260 m crosses a platform of a certain length in 25.5 seconds. Whereas the passenger train of length 240 m can cross the same platform in 30 seconds. Find the relative speed of both trains when they cross each other in the same direction. 
1. 11/3 m/s
2. 13/3 m/s
3. 17/3 m/s
4. 19/3 m/s
5. 16/3 m/s

Answer 1

Correct Answer - Option 1 : 11/3 m/s

Given:

Speed of train = 72 kmph

Formula used:

Speed = Distance/Time

Relative speed = S₁ – S₂          (S₁, S₂ are speed, S₁ > S₂)

Calculation:

Speed of train = 72kmph = 72 × 5/18 = 20 m/s

Let Length of the platform be A m.

According to the question,

(A + 260)/20 = 25.5

⇒ A = 250 m

Let the speed of passenger train be M m/s.

⇒ (240 + 250)/30 = M

⇒ M = 49/3 m/s

∴ Relative speed of two trains = 20 – 49/3 = 11/3 m/s