document.write( "Question 1060598: Write and solve an equation: in two hours, a motorboat can travel 8 miles down a river and return 4 miles back. If the river flows at 2 miles per hour, how fast can the boat travel in still water?\r
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Algebra.Com's Answer #675545 by ikleyn(52777) $\"\"$ $\"About$

You can put this solution on YOUR website!
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\n" ); document.write( "Write and solve an equation: in two hours, a motorboat can travel 8 miles down a river and return 4 miles back.
\n" ); document.write( "If the river flows at 2 miles per hour, how fast can the boat travel in still water?\r
\n" ); document.write( "\n" ); document.write( "(If possible, can you show a step by step solution? I have a final coming up soon and this is a study guide question!)
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document.write( "Let \"u\" be the boat speed in still water.\r\n" );
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document.write( "Then  the boat speed traveling downstream is u+2 mph,\r\n" );
document.write( "while the boat speed traveling  upstream  is u-2 mph.\r\n" );
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document.write( "The boat travels 8 miles downstream in  hours.\r\n" );
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document.write( "The boat travels 4 miles  upstream  in  hours.\r\n" );
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document.write( "According to the condition,\r\n" );
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document.write( " = .\r\n" );
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document.write( "To solve it, multiply both sides by (u+2)*(u-2). You will get\r\n" );
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document.write( "8(u-2) = 4(u+2).\r\n" );
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document.write( "Simplify and solve:\r\n" );
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document.write( "8u - 16 = 4u + 8,\r\n" );
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document.write( "8u - 4u = 8 + 16,\r\n" );
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document.write( "4u = 20   --->  u =  = 5.\r\n" );
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document.write( "Anser.  The boat speed in still water is 5 miles per hour.\r\n" );
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\n" ); document.write( "\n" ); document.write( "Solved.\r
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\n" ); document.write( "\n" ); document.write( "It is standard, canonical and commonly used way to solve the problem and to represent/to explain the solution.\r
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\n" ); document.write( "\n" ); document.write( "Ignore writing by \"josgarithmetic\".\r
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