Two trains 120 m and 150 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 from the following answers:
A) 10.9 sec
B) 14.8 sec
C) 10.6 sec
D) 10.8 sec
E) 9.27 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 + 150= 
<gadget id="calculator">120 + 150</gadget>
<output>270</output>
270 m.   Required time= 270* 9/250 = 9.27   = 9.27 sec.   Answer: 9.27 sec
<result>E</result>
Two trains 120 m and 150 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?