Two train 200 m and 150 m long are running on parallel rails at the rate of 40 kmph and 45 kmph respectively. In how much time will they cross each other, if they are running in the same direction? Answers
A) 80 sec B) 252 sec C) 320 sec D) 330 sec E) None
Sol.   Relative speed = (45 - 40)= 
<gadget id="calculator">(45 - 40)</gadget>
<output>5</output>
5 kmph= [5 * 5/18] m/sec = 25/18 m/sec.   Total distance covered = Sum of lengths of trains = 350 m.   ∴ Time taken = [350 * 18/25= 
<gadget id="calculator">350 * 18/25</gadget>
<output>252</output>
252 sec.   Answer 252 sec
<result>B</result>
Two train 200 m and 150 m long are running on parallel rails at the rate of 40 kmph and 45 kmph respectively. In how much time will they cross each other, if they are running in the same direction?