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 54 seconds. What is the length of each train (in meters)?
Options:  A) 45  B) 55  C) 65  D) 75  E) 85
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 54 seconds, the relative difference in distance traveled is  54 * 25/9= 
<gadget id="calculator"> 54 * 25/9</gadget>
<output>150</output>
150 meters   This distance is twice the length of each train.   The length of each train is  150/2= 
<gadget id="calculator"> 150/2</gadget>
<output>75</output>
75 meters   The answer is 75.
<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 54 seconds. What is the length of each train (in meters)?