Two trains 140 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?
Answers.
A) 7  B) 8.2  C) 2  D) 10.8  E) 11.2
Answer: Option D   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 = 140 + 160= 
<gadget id="calculator">140 + 160</gadget>
<output>300</output>
300 m.   Required time= 300 * 9/250 = 54/5= 
<gadget id="calculator">54/5</gadget>
<output>54/5 = around 10.8</output>
10.8 sec
<result>D</result>
Two trains 140 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?