document.write( "Question 1129853: Janet and Michael took a canoeing trip, traveling 6 miles upstream along a river, against a 2 mi/h current. They then returned downstream to all the starting point of their trip. If their entire trip took 4 hours, what was their rate in still water? \r
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Algebra.Com's Answer #746485 by ikleyn(52781) $\"\"$ $\"About$

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document.write( "Let x be the rate of the canoe in still water.\r\n" );
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document.write( "Then the effective rate upstream is (x-2) miles per hour, and the time upstream is   hours.\r\n" );
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document.write( "The effective rate downstream is (x+2) miles per hour, and the time downstream is   hours.\r\n" );
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document.write( "So, your time equation is\r\n" );
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document.write( "     +  = 4.\r\n" );
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document.write( "Multiply both sides by (x-2)*(x+2). You will get\r\n" );
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document.write( "    6*(x+2) + 6*(x-2) = 4*(x-2)*(x+2)\r\n" );
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document.write( "    6x + 12 + 6x - 12 = 4(x^2 - 4)\r\n" );
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document.write( "    12x = 4x^2 - 16\r\n" );
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document.write( "    4x^2 - 12x - 16 = 0\r\n" );
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document.write( "    x^2 - 3x - 4 = 0\r\n" );
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document.write( "    (x-4)*(x+1) = 0.\r\n" );
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document.write( "Only positive root x= 4 is meaningful.\r\n" );
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document.write( "Answer.  The rate of the canoe in still water is 4 miles per hour.\r\n" );
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\n" ); document.write( "\n" ); document.write( "It is a typical and standard Upstream and Downstream round trip word problem.\r
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\n" ); document.write( "\n" ); document.write( "You can find many similar fully solved problems on upstream and downstream round trips with detailed solutions in lessons \r
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\n" ); document.write( "\n" ); document.write( "    - More problems on upstream and downstream round trips \r
\n" ); document.write( "\n" ); document.write( "    - Wind and Current problems solvable by quadratic equations \r
\n" ); document.write( "\n" ); document.write( "    - Unpowered raft floating downstream along a river\r
\n" ); document.write( "\n" ); document.write( "    - Selected problems from the archive on the boat floating Upstream and Downstream \r
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\n" ); document.write( "\n" ); document.write( "Read them attentively and learn how to solve this type of problems once and for all.\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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