Question

Two trains of equal lengths take 15 seconds and 30 seconds respectively to cross a telegraph post. If the length of each train be 120 metres, in what time will they cross each other travelling in opposite direction?

A 24 sec Correct Answer Incorrect Answer
B 20 sec Correct Answer Incorrect Answer
C 36 sec Correct Answer Incorrect Answer
D 16 sec Correct Answer Incorrect Answer

Solution

Speed of the first train = [120/15] m/sec = 8 m/sec Speed of the second train = [120/30] m/sec = 4 m/sec Speed = (8 + 4) m/sec = 12 m/sec Required time = (120 + 120)/12 sec = 20 sec

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