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 ?  Select:
A) 1:3 B) 3:2 C) 3:5 D) 3:7 E) None of these
Explanation:   Let the speeds of the two trains be x m/sec and y m/sec respectively.   Then, length of the first train = 27x metres,   Length of the second train = 17y metres.   [because distance = speed*time]   27x+17y /x+y=23   =&gt;27x+17y=23x+23y   =&gt;4x=6y   =&gt;x/y=6/4   So ratio of the speeds of train is 3:2   Option 3:2
<result>B</result>
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 ?