Two trains of equal length are running on parallel lines in the same direction at 46 km/hr and 36 km/hr. The faster train catches and completely passes the slower train in 72 seconds. What is the length of each train (in meters)?
Choose the correct answer:
A) 70  B) 80  C) 90  D) 100  E) 110
The relative speed = 46 - 36= 
<gadget id="calculator">46 - 36</gadget>
<output>10</output>
10 km/hr= 10 * 5/18 = 25/9 m/s   In 72 seconds, the relative difference in distance traveled is  72 * 25/9= 
<gadget id="calculator"> 72 * 25/9</gadget>
<output>200</output>
200 meters   This distance is twice the length of each train.   The length of each train is  200/2= 
<gadget id="calculator"> 200/2</gadget>
<output>100</output>
100 meters   The answer is 100.
<result>D</result>
Two trains of equal length are running on parallel lines in the same direction at 46 km/hr and 36 km/hr. The faster train catches and completely passes the slower train in 72 seconds. What is the length of each train (in meters)?