document.write( "Question 1159231: Ed can row 5 km downstream in half the time it takes him to row 5 km upstream. If the current is 2 km/hour, how fast can Ed row in still water. \n" ); document.write( "

Algebra.Com's Answer #782203 by ikleyn(52778) $\"\"$ $\"About$

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document.write( "Let r be his rate in still water.\r\n" );
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document.write( "Then the rate downstream is (r+2) km/h; while the rate upstream is (r-2) km/h.\r\n" );
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document.write( "The time to travel 5 km downstream is  ;  The time to travel 5 kn upstream is  .\r\n" );
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document.write( "Now your equation becomes\r\n" );
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document.write( "     = .\r\n" );
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document.write( "To solve it, cross multiply\r\n" );
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document.write( "    5*(r+2) = 2*5*(r-2).\r\n" );
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document.write( "Simplify and solve\r\n" );
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document.write( "    5r + 10 = 10r - 20\r\n" );
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document.write( "    10 + 20 = 10r - 5r\r\n" );
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document.write( "    30      = 5r\r\n" );
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document.write( "     r      = 30/5 = 6.\r\n" );
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document.write( "ANSWER.  Ed's rate in still water is 6 km/h.\r\n" );
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