document.write( "Question 618660: a train travelling at 60 mph takes 6 sec to enter a tunnel and a further 30 sec to pass completely through the tunnel. what is the length of the train and what is the length of the tunnel.
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Algebra.Com's Answer #389036 by Edwin McCravy(20056) $\"\"$ $\"About$

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document.write( "Since 1 hour is 3600 seconds,\r\n" );
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document.write( " 1 second is 1/3600th of an hour, so\r\n" );
document.write( " 6 seconds is 6/3600ths of an hour of 1/600th of an hour\r\n" );
document.write( "30 seconds is 30/3600ths of an hour of 1/120th of an hour\r\n" );
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document.write( "Let the train's length be x mi.\r\n" );
document.write( "Let the tunnel's length by y mi.\r\n" );
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document.write( "When the front of the train is at the tunnel entrance,\r\n" );
document.write( "the rear of the train is x mi. from the tunnel entrance.\r\n" );
document.write( "It then takes the rear of the train 1/600th of an hour\r\n" );
document.write( "to get to the entrance of the tunnel.  In that time the \r\n" );
document.write( "rear of the train has traveled exactly one train-length \r\n" );
document.write( "or x mi (to get to the tunnel entrance).\r\n" );
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document.write( "DISTANCE = RATE·TIME so\r\n" );
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document.write( "       x = 60· =  =  of a mile.\r\n" );
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document.write( "So the train is  of a mile long. (which is 528 feet)\r\n" );
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document.write( "It then takes 1/120th of an hour for the rear of the train to\r\n" );
document.write( "get from the tunnel entrance to the tunnel exit.  In\r\n" );
document.write( "that time the rear of the train has traveled exactly one \r\n" );
document.write( "tunnel-length or y mi.\r\n" );
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document.write( "DISTANCE = RATE·TIME so\r\n" );
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document.write( "       y = 60· =  =  of a mile.\r\n" );
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document.write( "So the tunnel is  of a mile long. \r\n" );
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document.write( "Edwin

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