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 2 sec. What is the length of the fast train?
Choose the correct choice from the following answers
A) 11 1/9 m B) 11 7/4 m C) 11 7/2 m D) 11 7/9 m E) 11 7/7 m
Relative speed = (40 - 20)= 
<gadget id="calculator">(40 - 20)</gadget>
<output>20</output>
20 km/hr.= 20 * 5/ 18 = 50/9 m/sec.   Length of faster train = 50/9 * 2 = 100/9 = 11 1/9 m.11 1/9 mnswer:11 1/9 m
<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 2 sec. What is the length of the fast train?