Two trains of equal length, running in opposite directions, pass a pole in 18…
2024
Two trains of equal length, running in opposite directions, pass a pole in 18 and 12 seconds. The trains will cross each other in
Answer: B. 14.4 sec — Solution: Let the length of each train be L. When a train passes a pole, time = length/speed. So the speeds are L/18 and L/12. Since the trains move in…
- A.
13.4 sec
- B.
14.4 sec
- C.
16.4 sec
- D.
15.4 sec
Attempted by 27 students.
Show answer & explanation
Correct answer: B
Solution: Let the length of each train be L.
When a train passes a pole, time = length/speed. So the speeds are L/18 and L/12.
Since the trains move in opposite directions, relative speed = L/18 + L/12 = (1/18 + 1/12)·L = (5/36)·L.
Distance to be covered when they cross each other = sum of lengths = 2L. Time to cross = distance ÷ relative speed = 2L ÷ (5L/36) = 72/5 = 14.4 seconds.
Answer: 14.4 sec