Two trains are running at 40 km/hr and 20 km/hr respectively in the same direction. Fast train completely passes a man sitting in the slower train in 3 seconds. What is the length of the fast train ?  Pick one: A) 27 7/9 B) 16 2/3 C) 29 7/9 D) 30 7/9 E) None of these
Explanation:   As Trains are moving in same direction,   So, Relative Speed = 40-20= 
<gadget id="calculator">40-20</gadget>
<output>20</output>
20 kmph= 20*(5/18) = 50/9 m/sec   Length of Train= Speed * Time   Length=50/9âˆ—3   =150/9   =16 2/3   Option 16 2/3
<result>B</result>
Two trains are running at 40 km/hr and 20 km/hr respectively in the same direction. Fast train completely passes a man sitting in the slower train in 3 seconds. What is the length of the fast train ?