Difficulty: Medium
Correct Answer: 82 km/hr
Explanation:
Given Data
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.
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