A train 300m long takes 9 sec to cross a man walking at 3kmph in a direction opposite to that of the train. Find the speed of the train? Choose the correct choice from the following options.
A) 100kmph B) 90kmph C) 120kmph D) 117kmph E) 125kmph
Let the speed of the train be x kmph   Speed of the train relative to man = x+3 = (x+3)*5/18 m/sec   300/[(x+3)*5/18] = 9   9(x+3) = 1080   x = 117kmph   Answer is 117kmph
<result>D</result>
A train 300m long takes 9 sec to cross a man walking at 3kmph in a direction opposite to that of the train. Find the speed of the train?