The speeds of two parallel running trains are in the ratio 5 : 4. Moving in opposite directions, they take 6 seconds each to pass a stationary signal post. Find the total time they take to cross each other completely. MCQ with Answer and Explanation
The speeds of two parallel running trains are in the ratio 5 : 4. Moving in opposite directions, they take 6 seconds each to pass a stationary signal post. Find the total time they take to cross each other completely.
A. 6.0 seconds
B. 6.6 seconds
C. 5.4 seconds
D. 7.2 seconds
Answer: Option A
Solution (By JKSSB Mock Tests)
Let the speeds be 5x and 4x. Length of first train = 5x * 6 = 30x. Length of second train = 4x * 6 = 24x. Total passing distance = 30x + 24x = 54x. Relative speed = 5x + 4x = 9x. Time taken to cross each other = 54x / 9x = 6 seconds.
A man can walk a certain distance in 6 hours and ride back in 2 hours. If he rides both ways, he will save 2 hours. How much time will he take if he walks both ways?
Explanation:
Let W be walking time one way and R be riding time one way. W + R = 6 + 2 = 8 hours (total trip: walk one way, ride back). If he rides both ways, total time is 2R. He saves 2 hours, so 2R = 8 - 2 = 6 hours => R = 3 hours. From W + R = 8, W = 5 hours. Walking both ways takes 2W = 10 hours.
A train 100 meters long running at 90 km/h crosses another train 150 meters long running at 54 km/h in the same direction. How much time do they take to cross each other?
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