document.write( "Question 224698: A cyclist rides 30 miles at an average speed of 9 miles/hr. At what rate must the cyclist cover the next 10 miles in order to bring the overall average speed up to 10 miles/hr? \n" ); document.write( "

Algebra.Com's Answer #167858 by Edwin McCravy(20059) $\"\"$ $\"About$

You can put this solution on YOUR website!
A cyclist rides 30 miles at an average speed of 9 miles/hr. At what rate must the cyclist cover the next 10 miles in order to bring the overall average speed up to 10 miles/hr?
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document.write( "Make this chart:\r\n" );
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document.write( "                    DISTANCE     RATE       TIME\r\n" );
document.write( "First part of trip     30         9         30/9\r\n" );
document.write( "Last part of trip      10         R         10/R\r\n" );
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document.write( "Whole trip             40        10         40/10\r\n" );
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document.write( "Let R be the rate required for the last part of the trip.\r\n" );
document.write( "So fill in the Distances and the rate\r\n" );
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document.write( "Add the distances and get 40 miles. Fill that in:\r\n" );
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document.write( "                    DISTANCE     RATE       TIME\r\n" );
document.write( "First part of trip     30         9         \r\n" );
document.write( "Last part of trip      10         R        \r\n" );
document.write( "-------------------------------------------------\r\n" );
document.write( "Whole trip             40        10         \r\n" );
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document.write( "Use  to fill in the times \r\n" );
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document.write( "                    DISTANCE     RATE       TIME\r\n" );
document.write( "First part of trip     30         9         30/9\r\n" );
document.write( "Last part of trip      10         R         10/R\r\n" );
document.write( "-------------------------------------------------\r\n" );
document.write( "Whole trip             40        10         40/10\r\n" );
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document.write( "To get the equation, realize that\r\n" );
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document.write( "TIME FOR FIRST PART + TIME FOR LAST PART = TOTAL TIME FOR TRIP\r\n" );
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document.write( "Solve that and get R=15 miles/hr\r\n" );
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document.write( "Edwin

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