Multiple choice general knowledge sports

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:

  1. 1/2

  2. 3/2

  3. 1/6

  4. None of these
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Ratio 3:2 is correct. If train lengths are L1, L2 and speeds v1, v2, then L1/v1=27, L2/v2=17, and (L1+L2)/(v1+v2)=23. Substituting L1=27v1, L2=17v2: (27v1+17v2)/(v1+v2)=23. Solving: 27v1+17v2=23v1+23v2, so 4v1=6v2, giving v1:v2=3:2.

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