Two bullet train s 140 m and 180 m long run at the speed of 60 km/hr and 40 km/hr respectively in opposite directions on parallel tracks. The time (in seconds) which they take to cross each other, is:  Answers.
A) 15.8 sec.	B) 11.52 sec.	C) 11.8 sec.	D) 10.8 sec.	E) 08.8 sec.
Relative speed = (60 + 40) km/hr = 100x5/18 = 250/9 m/ sec.   Distance covered in crossing each other = (140 + 180)= 
<gadget id="calculator">(140 + 180)</gadget>
<output>320</output>
320 m.   Required time= 320x9/250 = 11.52 sec.   ANSWER 11.52 sec.
<result>B</result>
Two bullet train s 140 m and 180 m long run at the speed of 60 km/hr and 40 km/hr respectively in opposite directions on parallel tracks. The time (in seconds) which they take to cross each other, is: