Two trains 120 m and 190 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?
Choose the correct choice:  A) 10.9 sec  B) 11.6 sec  C) 10.6 sec  D) 10.8 sec  E) 20.8 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 = 120 + 190= 
<gadget id="calculator">120 + 190</gadget>
<output>310</output>
310 m.   Required time= 310 * 9/250 = 11.6   = 11.6 sec.   Answer: 11.6 sec
<result>B</result>
Two trains 120 m and 190 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?