A train 1 mile long travels at a constant speed of 60 miles per hour through a tunnel that is also 1 mile long. How much time elapses from the moment the front of the train enters the tunnel until the back of the train completely exits it?
2 minutes
For the entire train to clear the tunnel, the front of the train must travel the length of the tunnel plus the length of the train itself, which is 1 + 1 = 2 miles. At 60 mph (1 mile per minute), traveling 2 miles takes 2 minutes.
About this riddle
Math riddles hide a calculation inside a short story. Pull out the numbers, work out what is being asked, and watch for a trick such as a unit change.
Difficulty: Hard. More like this: Math riddles with answers or try Target 24 for a different kind of puzzle.
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