Two trains 180 m and 160 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  B) 10.7  C) 10.3  D) 10.8  E) 12.24
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 = 180 + 160= 
<gadget id="calculator">180 + 160</gadget>
<output>340</output>
340 m.   Required time= 340 * 9/250 = 306/25= 
<gadget id="calculator">306/25</gadget>
<output>306/25 = around 12.24</output>
12.24sec.   'Answer: 12.24
<result>E</result>
Two trains 180 m and 160 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?