document.write( "Question 1163114: Jennifer drove 300 miles to see her friend. On the return trip, she drove 10 mph faster, so she made the return trip in 1 hour less time. What was her speed on the way to friend's home. \n" ); document.write( "

Algebra.Com's Answer #787092 by ikleyn(52799) $\"\"$ $\"About$

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document.write( "Let x be the rate (in miles per hour) going to friend's home.\r\n" );
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document.write( "Then the speed going back is (x+10) mph.\r\n" );
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document.write( "The time going to there is    hours.\r\n" );
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document.write( "The time going back is    hours.\r\n" );
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document.write( "The \"time\" equation is  \r\n" );
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document.write( "     -  = 1   hour.\r\n" );
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document.write( "The solution/(the answer) is just seen from here:  x = 50 mph.\r\n" );
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document.write( "To get formal algebra solution, multiply both sides by x*(x+10).  You will get\r\n" );
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document.write( "    300*(x+10) - 300x = x*(x+10)\r\n" );
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document.write( "    300x + 3000 - 300x = x^2 + 10x\r\n" );
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document.write( "    x^2 + 10x - 3000 = 0\r\n" );
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document.write( "    (x-50)*(x+60) = 0\r\n" );
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document.write( "    and  x= 50 is the only meaningful positive solution.\r\n" );
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document.write( "ANSWER.  The rate going to friend's home was  50 mph.\r\n" );
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document.write( "CHECK.    -  = 6 - 5 = 1 hour.   ! Correct !\r\n" );
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\n" ); document.write( "\n" ); document.write( "Using \"time\" equation is a STANDARD method of solving such problems.\r
\n" ); document.write( "\n" ); document.write( "From this lesson, 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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