Question
The speed of train A is 120 km/h and it takes 15 seconds
to cross a pole. Find the approximately time taken by train A to cross train B that is running with the speed 72 km/h in the same direction, and the length of train B is 540 meters.Solution
Speed of Train A = 120 km/h = (120 × 5/18) = 100/3 m/s
Length of Train A = 100/3 × 15 = 500 meters
Relative speed = 120 - 72 = 48 km/h = (48 × 5/18) = 40/3 m/s
Total Distance = 500 + 540 = 1040 meters
Time = 1040/(40/3) = 78 seconds
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