document.write( "Question 8175: a mississippi riverboat can travel 75 kilometers downstream in three hours and can make the return trip in five hours. find the speed of the boat in still water. \n" ); document.write( "

Algebra.Com's Answer #4510 by longjonsilver(2297) $\"\"$ $\"About$

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let speed of boat in still water = x
\n" ); document.write( "let speed of water = w\r
\n" ); document.write( "\n" ); document.write( "so we know:\r
\n" ); document.write( "\n" ); document.write( "with water, spped of boat = x+w
\n" ); document.write( "against water, speed of boat = x-w\r
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\n" ); document.write( "\n" ); document.write( "now speed=distance/time\r
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\n" ); document.write( "\n" ); document.write( "so, with water: \r
\n" ); document.write( "\n" ); document.write( "x+w = 75/3
\n" ); document.write( "x+w = 25\r
\n" ); document.write( "\n" ); document.write( "against water:\r
\n" ); document.write( "\n" ); document.write( "x-w = 75/5
\n" ); document.write( "x-w = 15\r
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\n" ); document.write( "\n" ); document.write( "seeing as how we want x, lets get rid of w by adding the 2 equations together to give 2x = 40 --> x = 20km/hr\r
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\n" ); document.write( "\n" ); document.write( "this is your answer.\r
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\n" ); document.write( "\n" ); document.write( "jon.
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