The train consists of 6 carriages, 20 meters long each. The gap between the carriages is 1 meter. If the train is moving at a constant speed of 60 kmh, how much time will it take the train to run through a 1 kilometer tunnel?
(D) 2 minutes
minutesSource: GMAT Club Tests
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a) It helps to keep a few pointers in mind always, and one such pointer is that 60KM/hr = 1 KM/min
b) For an object of "zero" length itself (like a point object), it would take 1 Minute to cross the tunnel
c) The train has a length of 6*20 + 5*1 = 125 m, or 0.125 KM; Using pointer in "(a)" above, it would take 0.125 or 1/8 minutes
Hence, total time to cross the tunnel is 1+ 1/8 minutes. Hence Option A.
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