Question
Two trains of equal lengths take 20 seconds and 30
seconds respectively to cross a telegraph post. If the length of each train be 300 metres, in what time will they cross each other travelling in opposite direction?Solution
Speed of the first train = (300/20) m/sec = 15 m/sec Speed of the second train = (300/30) m/sec = 10 m/sec Speed = (15 + 10) m/sec = 25 m/sec Required time = (300 + 300)/25 sec = 24 sec
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