Two trains of equal length cross a pole in 10 seconds and 20 seconds respectively. If the length of each train is 100 meters, find the time taken by them to pass each other when running in opposite directions. MCQ with Answer and Explanation
Two trains of equal length cross a pole in 10 seconds and 20 seconds respectively. If the length of each train is 100 meters, find the time taken by them to pass each other when running in opposite directions.
A. 14.50 seconds
B. 13.33 seconds
C. 12.24 seconds
D. 15.00 seconds
Answer: Option B
Solution (By JKSSB Mock Tests)
Speed of first train = 100 / 10 = 10 m/s. Speed of second train = 100 / 20 = 5 m/s. Total distance to cross = 100 + 100 = 200 meters. Relative speed in opposite directions = 10 + 5 = 15 m/s. Time taken = 200 / 15 = 13.33 seconds.
A generic bullet train covers a distance between two stations in 2 hours 30 minutes at a speed of 120 km/h. How much time will it take to cover the same distance at a speed of 150 km/h?
A motorboat covers a certain distance downstream in a river in 3 hours and returns upstream in 4 hours. If the speed of the river current is 3 km/h, find the speed of the motorboat in still water.
Explanation:
Let speed of boat in still water be v. Downstream speed = v + 3, Upstream speed = v - 3. Distance is same, so 3(v + 3) = 4(v - 3) => 3v + 9 = 4v - 12 => v = 21 km/h.
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