A train 140 meters long takes 6 seconds to cross a man walking at 5 kmph in the direction opposite to that of the train. Find the speed of the train.  Select:
A) 45 kmph
B) 50 kmph
C) 55 kmph
D) 60 kmph
E) 79 kmph
Explanation:   Let the speed of the train be x kmph.   Speed of the train relative to man = (x + 5) kmph = (x + 5) ×5/18 m/sec.   Therefore 140/((x+5)×5/18)=6 &lt;=&gt; 30 (x + 5) = 2520 &lt;=&gt; x = 79   Speed of the train is 79 kmph.   Answer: Option 79 kmph
<result>E</result>
A train 140 meters long takes 6 seconds to cross a man walking at 5 kmph in the direction opposite to that of the train. Find the speed of the train.