Two trains 50 m and 120 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?	Answers:	A) 10.9 sec	B) 14.8 sec	C) 6.12 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 = 50 + 120= 
<gadget id="calculator">50 + 120</gadget>
<output>170</output>
170 m.   Required time= 170 * 9/250= 
<gadget id="calculator">170 * 9/250</gadget>
<output>153/25 = around 6.12</output>
6.12= 6.12 sec.   Answer: 6.12 sec
<result>C</result>
Two trains 50 m and 120 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?