document.write( "Question 1153205: susan could run 16 miles at 4 mph and then run 8 miles at 2 mph. What should be her speed for 6 miles so that her overall average speed would be 3 mph? thanks! \n" ); document.write( "

Algebra.Com's Answer #775393 by ikleyn(52799) $\"\"$ $\"About$

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\n" ); document.write( "susan could run 16 miles at 4 mph and then run 8 miles at 2 mph. What should be her speed for 6 $\"highlight%28additional%29\"$ miles
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document.write( "16 miles at 4 mph take   = 4 hours.\r\n" );
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document.write( "8 miles at 2 mph take   = 4 hours.\r\n" );
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document.write( "Let the time for additional 6 miles be  \"t\"  hours.\r\n" );
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document.write( "Then your equation is\r\n" );
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document.write( "     = 3  mph  (the desired average speed).\r\n" );
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document.write( "From the equation\r\n" );
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document.write( "     = 3,\r\n" );
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document.write( "    30 = 3*(8+t)\r\n" );
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document.write( "    30 = 24 + 3t\r\n" );
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document.write( "    30-24 = 3t,  \r\n" );
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document.write( "     6    = 3t\r\n" );
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document.write( "     t = 6/3 = 2 hours.\r\n" );
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document.write( "Hence, the last/additional 6 miles she should run at the average speed of   = 3 miles per hour.    ANSWER\r\n" );
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