document.write( "Question 1129852: A bakery delivery truck leaves the Bakery at 5:00am each morning on its 140-mike route. One day the drive gets a late start and does not leave the bakery until 5:30am. To finish her route on time the driver drives 5 miles per hour faster than Usual. At what speed does she usually drive? \n" ); document.write( "

Algebra.Com's Answer #746481 by ikleyn(52776) $\"\"$ $\"About$

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document.write( "Let r be the usual speed.\r\n" );
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document.write( "Then you have this \"time equation\"\r\n" );
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document.write( " -  = 0.5    of an hour.\r\n" );
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document.write( "280*(r+5) - 280*r = r*(r+5)\r\n" );
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document.write( "r^2 + 5r - 1400 = 0\r\n" );
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document.write( "(r+40)*(r-35) = 0\r\n" );
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document.write( "The only meaningful is the positive root  r = 35 miles per hour.    ANSWER\r\n" );
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document.write( "Check.    -  = 4 - 3.5 = 0.5  of an hour.   ! Correct !\r\n" );
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