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 5 seconds. What is the length of the fast train ? Choose the correct option:
A) 27 7/9
B) 28 7/9
C) 29 7/9
D) 30 7/9
E) None of these
Explanation:   27 7/9s 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=50/9∗5   =250/9   =27 7/9   Option 27 7/9
<result>A</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 5 seconds. What is the length of the fast train ?