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?  Choose one: A) 1 : 3 B) 3 : 2 C) 3 : 4 D) 4 : 3 E) 3 : 5
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,   and length of the second train = 17y metres.   ( 27x + 17y ) / (x+ y )= 23   =&gt; 27x + 17y = 23x + 23y   =&gt; 4x = 6y   =&gt; ( x/y ) = ( 3/2 )   Answer: 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?