How many seconds will a 500 metre long train take to cross a man walking with…
2024
How many seconds will a 500 metre long train take to cross a man walking with a speed of 3 km/hr in the direction of the moving train if the speed of the train is 63 km/hr?
- A.
25
- B.
30
- C.
40
- D.
45
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Correct answer: B
To find how long the train takes to pass the man, use relative speed and the formula time = distance ÷ speed.
The train's speed is 63 km/h and the man walks at 3 km/h in the same direction.
When two objects move in the same direction, their relative speed is the difference: 63 − 3 = 60 km/h.
Convert 60 km/h to m/s: 60 × 5/18 = 50/3 m/s.
The train must cover its own length relative to the man, so distance = 500 m. Time = distance ÷ speed = 500 ÷ (50/3) = 500 × 3/50 = 30 s.
Therefore, the train takes 30 seconds to cross the man.