document.write( "Question 188738: A worker drove to work traveling 65 miles per hour. He returned home traveling 55 miles per hour. What was his average speed if the entire trip took 4 hours? \n" ); document.write( "

Algebra.Com's Answer #141559 by Edwin McCravy(20063) $\"\"$ $\"About$

You can put this solution on YOUR website!
Alan made a slight error!
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document.write( "Suppose the distance between his home and his word is  miles.\r\n" );
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document.write( "Then his total distance is  miles\r\n" );
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document.write( "Using \r\n" );
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document.write( "His time going to work = \r\n" );
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document.write( "His time returning home = \r\n" );
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document.write( "Therefore his \r\n" );
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document.write( "The LCD is 715, so we multiply that fraction by \r\n" );
document.write( "but we write it as \r\n" );
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document.write( " miles per hour\r\n" );
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document.write( "Notice three things here:\r\n" );
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document.write( "1.  We did not even use the 4 hours!\r\n" );
document.write( "2.  The distance N miles between his home and work\r\n" );
document.write( "    canceled out.\r\n" );
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document.write( "This means that the time and the distance are independent\r\n" );
document.write( "of the average speed.\r\n" );
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document.write( "3.  Important!  To find the average speed, it does not \r\n" );
document.write( "    work to just average the two speeds! For that would \r\n" );
document.write( "    have been 60 mph not mph.\r\n" );
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document.write( "Edwin

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