Two trains, each 100 meters long, moving in opposite directions, completely pass each other in 24 seconds. If one train is moving twice as fast the other, then what is the speed of the faster train (in km/hr)? Select the correct option
A) 12 km/hr
B) 16 km/hr
C) 20 km/hr
D) 24 km/hr
E) 28 km/hr
Let the speed of the slower train be x m/s   Then, the speed of the faster train is 2x m/s   The relative speed is 3x m/s   (100 + 100)/24 = 3x   x = 25/9 m/s   So, the speed of the faster train is 50/9 = 50/9 * 18/5= 
<gadget id="calculator">50/9 * 18/5</gadget>
<output>20</output>
20 km/hr   The answer is 20 km/hr.
<result>C</result>
Two trains, each 100 meters long, moving in opposite directions, completely pass each other in 24 seconds. If one train is moving twice as fast the other, then what is the speed of the faster train (in km/hr)?