Two trains 100 m and 60 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) 5.76 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 = 100 + 60= 
<gadget id="calculator">100 + 60</gadget>
<output>160</output>
160 m.   Required time= 160 * 9/250= 
<gadget id="calculator">160 * 9/250</gadget>
<output>144/25 = around 5.76</output>
5.76= 5.76 sec.   Answer: 5.76 sec
<result>B</result>
Two trains 100 m and 60 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?