document.write( "Question 1050412: the boat goes downstream at 13 kph
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\n" ); document.write( "what is the speed of the current?
\n" ); document.write( "It is obvious it is ten kph, but how do you put this into an equation? \n" ); document.write( "

Algebra.Com's Answer #666007 by ikleyn(53765) $\"\"$ $\"About$

You can put this solution on YOUR website!
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\n" ); document.write( "the boat goes downstream at 13 kph
\n" ); document.write( "upstream it goes three kph
\n" ); document.write( "what is the speed of the current?
\n" ); document.write( "It is obvious it is ten kph, but how do you put this into an equation?
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document.write( "When the boat goes downstream, its speed relative to the river's bank is the sum of the boat rate in still water and the current rate.\r\n" );
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document.write( "When the boat goes upstream, its speed relative to the river's bank is the difference of the boat rate in still water and the current rate.\r\n" );
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document.write( "This it the key for solving \"Upstream-Downstream\" Travel and Distance problems.\r\n" );
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document.write( "So, your equations are\r\n" );
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document.write( "u + v = 13,    (1)    (u is the boat speed in still water,\r\n" );
document.write( "u - v =  3.    (2)     v is the currebt speed.)\r\n" );
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document.write( "Add the equations (1) and (2). You will get\r\n" );
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document.write( "2u = 13 + 3 = 16.   Hence,  u =  = 8 kph.\r\n" );
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document.write( "Then you can easily find v from (1): v = 13-8 = 5.\r\n" );
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document.write( "Answer.  The current speed is 5 kph.  The boat speed in still water is 8 kph.\r\n" );
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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( "    - 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( "    - Selected problems from the archive on the boat floating Upstream and Downstream \r
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