document.write( "Question 1196115: Flying against the wind, a jet travels 3600 miles in 4 hours. Flying with the wind, the same jet travels 7980 miles in 7 hours. What is the rate of the jet in still air and what is the rate of the wind?
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Algebra.Com's Answer #828820 by ikleyn(52797) $\"\"$ $\"About$

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\n" ); document.write( "Flying against the wind, a jet travels 3600 miles in 4 hours.
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document.write( "Flying against the wind, the jet' speed relative the earth surface is  \r\n" );
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document.write( "     = 900 miles per hour.\r\n" );
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document.write( "Flying with    the wind, the jet' speed relative the earth surface is  \r\n" );
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document.write( "     = 1140 miles per hour.\r\n" );
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document.write( "Let \"u\" be the jet' speed in still air and let \"v\" be the rate of the wind.\r\n" );
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document.write( "Then we have this system of equations\r\n" );
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document.write( "    u + v = 1140    (1)\r\n" );
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document.write( "    u - v =  900    (2)\r\n" );
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document.write( "Find \"u\" by adding equations (1) and (2)\r\n" );
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document.write( "    2u    = 1140+900 = 2040,  u = 2040/2 = 1020.\r\n" );
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document.write( "Find \"v\" by subtracting equation (2) from equation (1)\r\n" );
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document.write( "    v - (-v) = 1140-900,  2v = 240,  v = 240/2 = 120.\r\n" );
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document.write( "ANSWER.  The jet' speed in still air is 1020 miles per hour.\r\n" );
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document.write( "         The rate of the wind is 120 miles per hour.\r\n" );
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\n" ); document.write( "\n" ); document.write( "It is a typical \"tailwind and headwind\" word problem.\r
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\n" ); document.write( "\n" ); document.write( "See the lessons \r
\n" ); document.write( "\n" ); document.write( "    - Wind and Current problems \r
\n" ); document.write( "\n" ); document.write( "    - Wind and Current problems solvable by quadratic equations \r
\n" ); document.write( "\n" ); document.write( "    - Selected problems from the archive on a plane flying with and against the wind \r
\n" ); document.write( "\n" ); document.write( "in this site, where you will find other similar solved problems with detailed explanations.\r
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\n" ); document.write( "\n" ); document.write( "Also, you have this free of charge online textbook in ALGEBRA-I in this site\r
\n" ); document.write( "\n" ); document.write( "    ALGEBRA-I - YOUR ONLINE TEXTBOOK.\r
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\n" ); document.write( "\n" ); document.write( "The referred lessons are the part of this textbook under the section \"Word problems\", the topic \"Travel and Distance problems\".\r
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\n" ); document.write( "\n" ); document.write( "Save the link to this online textbook together with its description\r
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\n" ); document.write( "\n" ); document.write( "Free of charge online textbook in ALGEBRA-I
\n" ); document.write( "https://www.algebra.com/algebra/homework/quadratic/lessons/ALGEBRA-I-YOUR-ONLINE-TEXTBOOK.lesson\r
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\n" ); document.write( "\n" ); document.write( "to your archive and use it when it is needed.\r
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