Two trains 140 m and 170 m long run at the speed of 60 km/hr and 40 km/hr respectively in opposite directions on parallel tracks. The time which they take to cross each other is?  Select the correct option:
A) 10.9 sec
B) 10.1 sec
C) 10.6 sec
D) 10.8 sec
E) 11.16 sec
Relative speed = 60 + 40= 
<gadget id="calculator">60 + 40</gadget>
<output>100</output>
100 km/hr.= 100 * 5/18 = 250/9 m/sec.   Distance covered in crossing each other   = 140 + 170= 
<gadget id="calculator">140 + 170</gadget>
<output>310</output>
310 m.   Required time= 310 * 9/250= 
<gadget id="calculator">310 * 9/250</gadget>
<output>279/25 = around 11.16</output>
11.16 sec.   Answer:11.16 sec
<result>E</result>
Two trains 140 m and 170 m long run at the speed of 60 km/hr and 40 km/hr respectively in opposite directions on parallel tracks. The time which they take to cross each other is?