document.write( "Question 1036205: Two trains 100 meters and 120 meters long are running in the same directions with speed of 72 km/hr and 54 km./hr. in how much time will the first train cross the second? \n" ); document.write( "
Algebra.Com's Answer #650862 by ikleyn(52802)\"\" \"About 
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\n" ); document.write( "Two trains 100 meters and 120 meters long are running in the same directions with speed of 72 km/hr and 54 km./hr.
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\n" ); document.write( "\n" ); document.write( "Answer.  \"%28100%2B120%29%2F%2820-15%29\" = \"220%2F5\" = 44 seconds.\r
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document.write( "What is  20  in the denominator in the Answer?  It is  20 meters per second, \r\n" );
document.write( "   which is the speed of the first train,  72  kilometers per hour, converted to meters per second.\r\n" );
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document.write( "What is  15  in the denominator in the Answer?  It is  15 meters per second, \r\n" );
document.write( "   which is the speed of the second train,  54  kilometers per hour, converted to meters per second.\r\n" );
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document.write( "What is the difference  (20-15)  in the denominator?  It is the relative speed of the faster train to slower train\r\n" );
document.write( "   moving on parallel tracks in the same direction. \r\n" );
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document.write( "What is the sum  (100+120)  in the numerator?  It is the sum of the lengths of the two trains. \r\n" );
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document.write( "Why we divide  (100+120)  by  (20-15)?  It is the time required for the faster train to pass completely the slower train. \r\n" );
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\n" ); document.write( "\n" ); document.write( "See the lesson A train passing another train in this site.\r
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