A bullet train 120 m long is running with a speed of 50 kmph. In what time will it pass a man who is running at 4 kmph in the direction opposite to that in which the bullet train is going?  Pick one.
A) 23 sec
B) 15 sec
C) 12 sec
D) 8 sec
E) 16 sec
D   8 sec   Speed of the bullet train relative to man = (50 + 4)= 
<gadget id="calculator">(50 + 4)</gadget>
<output>54</output>
54 *5/18 m/sec= 45/3 m/sec.   Time taken by the bullet train to cross the man = Time taken by it to cover 120 m at (45/3) m / sec   = (120*3/45)= 
<gadget id="calculator">(120*3/45)</gadget>
<output>8</output>
8 sec
<result>D</result>
A bullet train 120 m long is running with a speed of 50 kmph. In what time will it pass a man who is running at 4 kmph in the direction opposite to that in which the bullet train is going?