Two trains running in opposite directions cross a man standing on the platform in 27 seconds and 17 seconds respectively and they cross each other in 23 seconds. The ratio of their speeds is:
Aptitude
Problems on Trains
Difficulty: Medium
Choose an option
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A3:2
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B4:3
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C5:4
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D7:5
Answer
Correct Answer: 3:2
Explanation
Given
- Train 1 passes a man in 27 s
- Train 2 passes a man in 17 s
- They cross each other in 23 s (opposite)
Let speeds be v1, v2 (m/s)Lengths: l1 = v1 × 27, l2 = v2 × 17Crossing: (l1 + l2)/(v1 + v2) = 23⇒ 27v1 + 17v2 = 23v1 + 23v2⇒ 4v1 = 6v2 ⇒ v1/v2 = 3:2