Correct Answer: 50 km/hr
Explanation:
Step 1: Understand the given information
Step 2: Use relative speed concept
Since the train and the man are moving in the same direction, we subtract the man's speed from the train's speed to get the relative speed.
Let the speed of the train be x km/h.
Relative speed = (x - 5) km/h = ((x - 5) × 1000) / 3600 m/s
Step 3: Use the formula: Distance = Speed × Time
Distance = 125 meters
Time = 10 seconds
Speed = Distance / Time = 125 / 10 = 12.5 m/s
Step 4: Solve for x
(x - 5) × 1000 / 3600 = 12.5
(x - 5) = (12.5 × 3600) / 1000
(x - 5) = 45
x = 50 km/h
Answer: 50 km/h
The speed of the train is 50 kilometers per hour.
This problem tests the understanding of relative speed in the same direction. Since the man and the train move in the same direction, the train takes longer to overtake him, and the effective speed is reduced. The use of basic distance = speed × time formula allows solving such problems efficiently.
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