Two trains of equal length travelling in opposite direction crosses a pole in…
2024
Two trains of equal length travelling in opposite direction crosses a pole in 18 sec and 12 sec respectively . In how much time two trains will cross each other ?
Answer: C. 14.4 sec — Answer: 14.4 sec Key idea: When two objects move in opposite directions, use the sum of their speeds as the relative speed. Let the length of each train be x…
- A.
15.5 sec
- B.
8.8 sec
- C.
14.4 sec
- D.
20.2 sec
Attempted by 21 students.
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Correct answer: C
Answer: 14.4 sec
Key idea: When two objects move in opposite directions, use the sum of their speeds as the relative speed.
Let the length of each train be x metres.
Speed of first train = x/18 m/s; speed of second train = x/12 m/s.
Relative speed (opposite directions) = x/18 + x/12 = 5x/36 m/s.
Distance to be covered for complete crossing = sum of lengths = 2x.
Time = distance ÷ relative speed = 2x ÷ (5x/36) = 2x × 36/(5x) = 72/5 = 14.4 seconds.
Therefore, the two trains will cross each other in 14.4 seconds.