Two trains, each 100 m long, moving in opposite directions, cross other in 4 sec. If one is moving twice as fast the other, then the speed of the faster train is? Choices.
A) 76 km/hr  B) 66 km/hr  C) 60 km/hr  D) 67 km/hr  E) 120 km/hr
Let the speed of the slower train be x m/sec.   Then, speed of the train = 2x m/sec.   Relative speed = ( x + 2x) = 3x m/sec.   (100 + 100)/4 = 3x =&gt; x = 50/3   So, speed of the faster train = 100/3 = 100/3 * 18/5= 
<gadget id="calculator">100/3 * 18/5</gadget>
<output>120</output>
120 km/hr.   Answer:120 km/hr
<result>E</result>
Two trains, each 100 m long, moving in opposite directions, cross other in 4 sec. If one is moving twice as fast the other, then the speed of the faster train is?