A train passes through a long tunnel in the mountains. The train is 125 meters long, and travels at 40 kilometers per hour
Just as the last car is completely inside the tunnel, a man begins walking from the end of the train to the front. He walks at 5 kilometers per hour and reaches the front of the train just as it emerges into the daylight.
How long is the tunnel?
Scroll down for the answer.
The Answer:
Let X = the length of the tunnel in meters. The man travels X meters at 45 kilometers per hour (the combined speed of the train and his walking) in the same time that the train travels X - 125 meters at 40 kilometers per hour.
The equation:
solves to:
Therefore, the length of the tunnel is 1125 meters.
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