document.write( "Question 1070505: A man takes 5 hours and 20 minutes to row 6 miles up a river and back. If he can row 3 miles downstream in the same time that he can row 1 mile upstream, find the rate at which he rows and the rate of the current.
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Algebra.Com's Answer #685586 by ikleyn(52798) $\"\"$ $\"About$

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\n" ); document.write( "A man takes 5 hours and 20 minutes to row 6 miles up a river and back. If he can row 3 miles downstream in the same time
\n" ); document.write( "that he can row 1 mile upstream, find the rate at which he rows and the rate of the current.
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document.write( "Let u be the rate of the boat at still water and v be the current rate (in miles-per-hour).\r\n" );
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document.write( "Then the speed of the boat downstream is (u+v) mph, \r\n" );
document.write( "while the speed of the boat  upstream is (u-v) mph.\r\n" );
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document.write( "Hence, you have these two equations for two unknowns\r\n" );
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document.write( " =        (1)   (\"A man takes 5 hours and 20 minutes to row 6 miles up a river and back\")\r\n" );
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document.write( " =            (2)   (\"he can row 3 miles downstream in the same time that he can row 1 mile upstream\")\r\n" );
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document.write( "Simplify equation (1) in this way:\r\n" );
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document.write( " =       (1') \r\n" );
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document.write( "and replace    in  (1')  by , based on (2). You will get\r\n" );
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document.write( " = ,    or\r\n" );
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document.write( " = ,   or   (u+v) =  = . \r\n" );
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document.write( "Then from (2)  u-v =  =  = .\r\n" );
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document.write( "You have now this system for u and v:\r\n" );
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document.write( "u + v = ,    (3)\r\n" );
document.write( "u - v = .    (4)\r\n" );
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document.write( "Add the two equations. You will get\r\n" );
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document.write( "2u =  =  = 6.   Hence,   u =  = 3 miles per hour.\r\n" );
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document.write( "Now from (3),  v =  =  = 1.5 miles per hour.\r\n" );
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document.write( "Answer.  The boat speed in still water is 3 miles per hour.\r\n" );
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document.write( "         The current speed is 1.5 miles per hour.\r\n" );
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\n" ); document.write( "\n" ); document.write( "You can find many fully solved problems on upstream and downstream round trips with detailed solutions in lessons \r
\n" ); document.write( "\n" ); document.write( "    - Wind and Current problems \r
\n" ); document.write( "\n" ); document.write( "    - More problems on upstream and downstream round trips \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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