Question
Two trains, each of length 120 m, are running in
opposite directions at speeds of 54 km/h and 72 km/h. In how many seconds will they completely cross each other?Solution
Convert speeds to m/s: 54 km/h = 54 × (5/18) = 15 m/s 72 km/h = 72 × (5/18) = 20 m/s Relative speed (opposite directions) = 15 + 20 = 35 m/s Total distance to be covered = 120 + 120 = 240 m Time = Distance / Speed = 240 / 35 = 48/7
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