Question
Two trains of equal lengths take 30 seconds and 45
seconds respectively to cross a telegraph post. If the length of each train be 450 metres, in what time will they cross each other travelling in opposite direction?Solution
Speed of the first train = [450/30] m/sec = 15 m/sec Speed of the second train = [450/45] m/sec = 10 m/sec Speed = (15 + 10) m/sec = 25 m/sec Required time = (450 + 450)/25 sec = 36 sec
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