Two trains each 250 m in length are running on the same parallel lines in opposite directions with the speed of 80 kmph and 70 kmph respectively. In what time will they cross each other completely?
Select.
A) 11 sec
B) 15 sec
C) 19 sec
D) 12 sec
E) 20 sec
12 sec   12 sec = 250 m + 250 m = 500 m   RS = 80 + 70= 
<gadget id="calculator">80 + 70</gadget>
<output>150</output>
150 * 5/18= 125/3   T = 500 * 3/125= 
<gadget id="calculator">500 * 3/125</gadget>
<output>12</output>
12 sec
<result>D</result>
Two trains each 250 m in length are running on the same parallel lines in opposite directions with the speed of 80 kmph and 70 kmph respectively. In what time will they cross each other completely?