document.write( "Question 1138861: At the airport, Person A and Person B are walking at the same speed to catch their flight, but Person B decides to step onto the moving sidewalk, while Person A continues to walk on the stationary sidewalk. If the sidewalk moves at 1 meter per second, and it takes Person B 30 seconds less to walk the 360-meter distance, at what speed are Person A and Person B walking? \n" ); document.write( "

Algebra.Com's Answer #756653 by ikleyn(52794) $\"\"$ $\"About$

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document.write( "Let x be the speed of A and B (the same (!) ) walking on the stationary sidewalk (in meters per second).\r\n" );
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document.write( "Then the effective speed of B on the moving sidewalk is (x+1) m/s.\r\n" );
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document.write( "The time equation is \r\n" );
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document.write( "     -  = 30 seconds.\r\n" );
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document.write( "Cancel the factor of 30 in both sides and then multiply both sides by x*(x+1).\r\n" );
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document.write( "    12(x+1) - 12x = x*(x+1)\r\n" );
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document.write( "    12            = x^2 + x\r\n" );
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document.write( "     x^2 + x - 12 = 0\r\n" );
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document.write( "     (x+4)*(x-3) = 0.\r\n" );
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document.write( "The roots are x= -4  and  x= 3, but only positive value x= 3 is the meaningful solution.\r\n" );
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document.write( "ANSWER.  The speed of A and B walking on stationary sidewalk is 3 meters per second.\r\n" );
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document.write( "CHECK.    -  = 120 - 90 = 30 seconds.   ! Correct !\r\n" );
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document.write( "     (Actually, it is very high speed for walking person.\r\n" );
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document.write( "      Usual speed walking is about 1 m/s, as everybody knows.\r\n" );
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document.write( "      I suspect that it would be much more realistic to have feet in this problem instead of meters !)\r\n" );
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\n" ); document.write( "\n" ); document.write( "Using \"time\" equation is the STANDARD method of solving such problems.\r
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\n" ); document.write( "\n" ); document.write( "To see many other similar solved problems by this method, 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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\n" ); document.write( "\n" ); document.write( "From these lessons, learn on how to write, how to use and how to solve a \"time\" equation.\r
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