How much time will a train of length 400 m moving at a speed of 72 kmph take to cross another train of length 300 m, moving at 36 kmph in the same direction? Choose the correct choice from the following answers.
A) 40 sec
B) 50 sec
C) 60 sec
D) 70 sec
E) 80 sec
The distance to be covered = Sum of their lengths = 400 + 300= 
<gadget id="calculator">400 + 300</gadget>
<output>700</output>
700 m.   Relative speed= 72 -36= 
<gadget id="calculator">72 -36</gadget>
<output>36</output>
36 kmph= 36 * 5/18= 
<gadget id="calculator">36 * 5/18</gadget>
<output>10</output>
10 mps.   Time required= d/s = 700/10= 
<gadget id="calculator">700/10</gadget>
<output>70</output>
70 sec.   ANSWER:70 sec
<result>D</result>
How much time will a train of length 400 m moving at a speed of 72 kmph take to cross another train of length 300 m, moving at 36 kmph in the same direction?