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 (in seconds) which they take to cross each other, is:
Pick:	A) 10.2	B) 10.9	C) 10.1	D) 10.8	E) 10.5
Explanation:   Relative speed = (60 + 40) km/hr =[ 100 x ( 5 / 18 ) ]m/sec = ( 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 x ( 9/250 ) ] sec = ( 54/ 5 )= 
<gadget id="calculator">( 54/ 5 )</gadget>
<output>54/5 = around 10.8</output>
10.8 sec.   Answer: 10.8) 10.8
<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 (in seconds) which they take to cross each other, is: