Two trains of equal lengths take 12 seconds and 20 seconds respectively to cross a pole. If the length of each train be 240 metre, in what time (in seconds) will they cross each other travelling in opposite direction ?

15

18

20

24

Speed of the first train = (240/12) m/sec = 20 m/sec. Speed of the second train = (240/20) m/sec = 12 m/sec. Relative speed = (20 + 12) = 32 m/sec. .'. Required time = (240+240)/32 = 480/32 = 15 sec.

Back To Top