A train 125m long takes 6 sec to cross a man walking at 5kmph in a direction opposite to that of the train. Find the speed of the train?  Choices:
A) 65kmph B) 70kmph C) 75kmph D) 80kmph E) 85kmph
Let the speed of the train be x kmph   Speed of the train relative to man = x+5 = (x+5)*5/18 m/sec   125/[(x+5)*5/18] = 6   30(x+5) = 2250   x = 70kmph   Answer is 70kmph
<result>B</result>
A train 125m long takes 6 sec to cross a man walking at 5kmph in a direction opposite to that of the train. Find the speed of the train?