Home » Aptitude » Problems on Trains

A train 108 m long moving at a speed of 50 km/hr crosses a train 112 m long coming from opposite direction in 6 seconds. The speed of the second train is:

Difficulty: Medium

Correct Answer: 82 km/hr

Explanation:

Given Data

  • Length of first train = 108 m
  • Speed of first train = 50 km/hr
  • Length of second train = 112 m
  • Time to completely cross each other = 6 s
  • Direction = opposite, so relative speed is additive

Step 1: Total distance to be covered
When two trains cross each other completely, relative distance = sum of lengths. Distance = 108 + 112 = 220 m


Step 2: Relative speed from distance and time
Relative speed = Distance ÷ Time = 220 ÷ 6 = 110/3 m/s ≈ 36.67 m/s


Step 3: Convert the known speed to m/s
Use 1 km/hr = 5/18 m/s Speed of first train = 50 × (5/18) = 125/9 m/s ≈ 13.89 m/s


Step 4: Find speed of the second train in m/s
Relative speed (opposite) = v1 + v2 v2 = (110/3) − (125/9) = (330 − 125)/9 = 205/9 m/s ≈ 22.78 m/s


Step 5: Convert v2 to km/hr
v2 (km/hr) = (205/9) × (18/5) = 82 km/hr


Final Answer
The speed of the second train is 82 km/hr.

← Previous Question Next Question→

More Questions from Problems on Trains

Discussion & Comments

No comments yet. Be the first to comment!
Join Discussion