document.write( "Question 1139188: Evan went on a bike ride of 120 miles. He realized that if he had gone 18 mph faster, he would have arrived 15 hours sooner. How fast did he actually ride?
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Algebra.Com's Answer #756962 by ikleyn(52909) $\"\"$ $\"About$

You can put this solution on YOUR website!
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\n" ); document.write( "\n" ); document.write( " It is a standard problem to be solved using the \"time\" equation.\r
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\n" ); document.write( "\n" ); document.write( " It was solved tens (if not hundred) times at this forum, so I will be short.\r
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document.write( "Let \"r\" be the actual speed, in miles per hour.\r\n" );
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document.write( "Then the hypothetical speed is (r+18) mph.\r\n" );
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document.write( "The \"time\" equation is\r\n" );
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document.write( "     -  = 15   hours.\r\n" );
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document.write( "Cancel the factor 15 in both sides \r\n" );
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document.write( "     -  = 1.\r\n" );
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document.write( "Now multiply both sides by r*(r+18), simplify and solve for \"r\"\r\n" );
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document.write( "   8*(r+18) - 8r = r*(r+18).\r\n" );
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document.write( "    8*18 = r*(r+18)\r\n" );
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document.write( "    r^2 + 18r - 144 = 0\r\n" );
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document.write( "    (r-6)*(r+24) = 0.\r\n" );
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document.write( "There are two roots, 6 and -24, and only positive value of r= 6 is the solution to the problem.\r\n" );
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document.write( "ANSWER.  Actual speed was  6 mph.    (Not much . . .)\r\n" );
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\n" ); document.write( "\n" ); document.write( "Using \"time\" equation is the STANDARD method of solving such problems.\r
\n" ); document.write( "\n" ); document.write( "From my post, learn on how to write, how to use and how to solve a \"time\" equation.\r
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\n" ); document.write( "\n" ); document.write( "To see many other similar solved problems, look into the lessons\r
\n" ); document.write( "\n" ); document.write( "    - Had a car move faster it would arrive sooner\r
\n" ); document.write( "\n" ); document.write( "    - How far do you live from school? \r
\n" ); document.write( "\n" ); document.write( "    - Earthquake waves \r
\n" ); document.write( "\n" ); document.write( "    - Time equation: HOW TO use, HOW TO write and HOW TO solve it \r
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